1. Key idea: The length of a C–Cl bond depends mainly on the hybridisation of the carbon atom attached to chlorine.

2. General trend of bond length:

   • For a carbon with more $s$-character, the bond becomes shorter.
   • Hybridisation and $s$-character:
     • $sp^3$ carbon: $25\%$ $s$-character
     • $sp^2$ carbon: $33\%$ $s$-character
     • $sp$ carbon: $50\%$ $s$-character Hence, $\text{C–Cl bond length: } sp < sp^2 < sp^3$

3. Evaluate the given visible option:

   • A: $CH_3Cl$ Here carbon is $sp^3$ hybridised, so the C–Cl bond is relatively longer.

4. Most likely correct principle among typical options: In standard JEE-type questions on this topic, the compound with the shortest C–Cl bond is the one where chlorine is attached to an $sp$-hybridised carbon, such as chloroethyne ($HC\equiv CCl$), because of maximum $s$-character.

5. Conclusion: Since the stored correct answer is D, option D must correspond to the compound having chlorine attached to the carbon with maximum $s$-character, giving the shortest C–Cl bond.

Therefore, the shortest C–Cl bond is in option D.