1. Given reaction

   $M + L \rightarrow C$

   where:

   • $M$ = metal ion
   • $L$ = ligand
   • $C$ = complex

2. Spectrophotometric condition

   We are told:

   • $M$ does not absorb light
   • $C$ does not absorb light
   • Only $L$ absorbs light

   Therefore, the measured absorbance $A$ depends only on the concentration of free ligand $L$ present in solution.

3. Before equivalence point

   As ligand is added, it reacts completely with metal ion:

   $M + L \rightarrow C$

   So, until all $M$ is consumed, essentially no free $L$ remains in solution.

   Hence absorbance remains approximately zero (or very small/constant) up to the equivalence point.

4. At equivalence point

   All metal ion has been converted into complex. Any further added ligand remains unreacted as free $L$.

5. After equivalence point

   Since only free $L$ absorbs, beyond the equivalence point the concentration of free $L$ increases with added volume of ligand.

   By Beer-Lambert law,

   $A \propto [L]_{\text{free}}$

   so absorbance increases linearly after the equivalence point.

6. Shape of the graph

   Thus the plot of absorbance $A$ vs volume of ligand $V$ is:

   • nearly horizontal at low absorbance before equivalence
   • then rises linearly after equivalence

   This corresponds to the graph with a break point at equivalence, with zero/constant absorbance first and increasing absorbance afterward.

7. Correct option

   This matches Option B.

Answer comparison

Stored correct answer: B

Derived answer: B

So, the derived answer agrees with the stored answer.