Topic: verb (ক্রিয়া),

Best Answer Explained in Below-:

In the sentence "I dreamt a wonderful dream," the term "dream" serves as a cognate object. A cognate object is a noun that is derived from the same root as the verb and is used to denote the action of that verb more specifically. In this case, the verb "dreamt" (from "dream") is complemented by "dream," which elaborates on the type of action being performed.

Cognate objects often provide additional detail or context to the verb, thus enriching the sentence's meaning. While it is already clear that the speaker performed the action of dreaming, the inclusion of "a wonderful dream" clarifies the quality of the dream experienced. Unlike a retained object, which is separate but still related to the verb (e.g., "I completed a project"), or a reflexive object, which refers back to the subject (e.g., "I enjoyed myself"), the cognate object directly ties back to the verb and enhances its meaning, establishing a deeper connection between the action and the experience. Therefore, "wonderful dream" aptly fits the definition of a cognate object, making option B the correct choice.