Step-by-step Solution:

1. Analyze Statement 1: "Micelles are formed by surfactant molecules above the critical micellar concentration (CMC)."

   • Surfactant molecules are amphipathic, meaning they have a hydrophilic (water-loving) head and a hydrophobic (water-fearing) tail.
   • In an aqueous solution at low concentrations, these molecules exist individually. They tend to accumulate at the surface, lowering the surface tension.
   • As the concentration of the surfactant is increased, it reaches a specific concentration known as the Critical Micelle Concentration (CMC).
   • Above the CMC, the surfactant molecules aggregate spontaneously to form structures called micelles. In these micelles, the hydrophobic tails are oriented towards the interior (away from the water), and the hydrophilic heads form the outer surface, interacting with the surrounding water.
   • This statement is the definition of the Critical Micelle Concentration. Therefore, Statement 1 is True.

2. Analyze Statement 2: "The conductivity of a solution having surfactant molecules decreases sharply at the CMC."

   • Let's consider an ionic surfactant, for example, sodium stearate ($C_{17}H_{35}COONa$). In solution, it dissociates into ions: $C_{17}H_{35}COO^-$ and $Na^+$.
   • Below the CMC, these ions are individual and mobile, contributing to the electrical conductivity of the solution. As concentration increases, the number of charge carriers increases, and so does the conductivity.
   • At and above the CMC, the surfactant anions ($C_{17}H_{35}COO^-$) aggregate to form a large micelle. A single micelle is an aggregate of many ions, but it carries a large net charge and moves as a single, large entity.
   • This large micelle has a much lower mobility than the individual small ions it is formed from, due to its increased size and mass. Furthermore, some of the counter-ions ($Na^+$) get associated with the surface of the micelle, which also reduces their effective mobility.
   • Because of this aggregation into less mobile particles, the molar conductivity ($\_Lambda_m$) of the solution shows a sharp decrease at the CMC. While the specific conductivity ($\_kappa$) continues to increase with concentration (as more ions are added), the rate of increase (the slope of the $\_kappa$ vs. concentration graph) decreases sharply at the CMC.
   • The statement is a common description of the electrical behavior at the CMC, referring to the sharp change caused by aggregation. Therefore, Statement 2 is True.

3. Analyze the relationship between Statement 1 and Statement 2.

   • Statement 1 describes the phenomenon of micelle formation.
   • Statement 2 describes one of the observable consequences of micelle formation. The change in conductivity is an effect caused by the aggregation of ions into micelles.
   • The reason for micelle formation (Statement 1) is the hydrophobic effect. The system minimizes the thermodynamically unfavorable contact between the hydrophobic tails and water molecules by forming these aggregates. This is the driving force.
   • Therefore, the change in conductivity (Statement 2) does not explain why micelles are formed (Statement 1). Instead, the formation of micelles (Statement 1) explains the sharp change in conductivity (Statement 2).
   • So, Statement 2 is not the correct explanation for Statement 1.

Conclusion:

• Statement 1 is True.
• Statement 2 is True.
• Statement 2 is NOT a correct explanation for Statement 1.

This corresponds to option B.