Topic: Redundancy,

Best Answer Explained in Below-:

In the sentence "He ordered for a cup of tea," the word "for" plays a crucial grammatical role. The question asks to identify a specific word in the sentence, and in this context, "for" is particularly significant because it indicates the purpose or intention behind the action of ordering.

The verb "ordered" typically requires a direct object, which in this case is "a cup of tea." However, the presence of the preposition "for" changes the construction to imply that the act of ordering was to obtain the cup of tea. This prepositional phrase (“for a cup of tea”) clarifies the reason for the order, emphasizing that the tea is not merely an object of the order but serves a functional purpose—it's what he was ordering for.

Additionally, "for" introduces an indirect relationship between the subject (He) and the object (a cup of tea), suggesting an underlying motivation. The other options (A: ordered, B: a, D: tea) do not carry this significant relational meaning seen with "for." Therefore, "for" is the word that encapsulates the intention behind the action, making it the correct answer.