The correct option is D b
Let’s examine the sentence: “He had no objection to forward my application to the higher authority.” The sentence uses the English phrase “no objection to” and the preposition “to” in it requires an object. The object can be a noun or a gerund. As “forward” is a verb, it cannot be an object to the preposition. The sentence requires the gerund “forwarding” in place of “forward.” Hence, error is in Part b of the sentence. So, Option B is the correct answer.