About the number of pairs which have $16$ as their H.C.F. and $136$ as their L.C.M., we can definitely say that:

Answer is D, no such pair exists as HCF does not divide LCM completely.

https://www.toppr.com/ask/question/about-the-number-of-pairs-which-have-16-as-their-hcf-and-136-as-their/