Solution

The order of $$\pi$$ π bond formation tendency is $$Si-O
This is because, with a decrease in the size from $$Si\rightarrow Cl$$, the effectiveness of the sideways overlap increases, and on moving from left to right along a period, the effective nuclear charge generally increases and consequently the energy of $$3d$$- orbital decreases from $$Si\rightarrow Cl$$.

Therefore, both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

Hence, option (A) is the correct answer.