The correct increasing order of trans-effect of the following species is:

The trans-effect series is an experimental order of ligands' ability to direct substitution to the position trans to themselves. The standard order is:
$${\text{CN}}^{-}\approx \text{CO}\approx {\text{C}}_2{\text{H}}_4>{\text{PH}}_3\approx {\text{H}}^{-}>{\text{CH}}_3^{-}\approx {\text{C}}_6{\text{H}}_5^{-}>{\text{NO}}_2^{-}>{\text{I}}^{-}>{\text{Br}}^{-}>{\text{Cl}}^{-}>{\text{NH}}_3\approx \text{py}>{\text{OH}}^{-}>{\text{H}}_2\text{O}$$
Increasing order (weakest to strongest): ${\text{NH}}_3<{\text{Br}}^{-}<{\text{C}}_6{\text{H}}_5^{-}<{\text{CN}}^{-}$.Thus, Option C correctly shows the highest to lowest sequence.