Thank you for reporting, we will resolve it shortly
Q.
The carbon-chlorine bond length is shortest in
NTA AbhyasNTA Abhyas 2020Chemical Bonding and Molecular Structure
Solution:
The carbon-chlorine bond length is shortest in $CH_{2}=CH-Cl$ as lone pair of Cl is involved in delocallisation due to which a double bond character develops between C and Cl-atoms.