Select the correct adjective form of act.

action
active
actant
act

The correct answer is D. I’d like to study biology or math, but choosing between the two will be difficult.

Explanation:

In grammar, a vague pronoun refers to a sentence in which it is not clear to which noun a pronoun such as it, this, which or that refers to. This occurs in the case of the sentence "I’d like to study biology or math, but it will be difficult" as it is not completely clear whether the pronoun "it" refers to "biology", "math" or to the situation of choosing between both. Because of this, in this sentence it is necessary to change the pronoun "it" and use a more specific pronoun or noun and therefore the sentence that corrects the vague pronoun problem is " I’d like to study biology or math, but choosing between the two will be difficult", considering this clarifies the pronoun "it" refers to choosing between the two subjects and does not change the first section of the sentence which is correct. Also, in this case, the use of "or", in the first part of the sentence implies the use of "them" to replace "biology or math" is not appropriate.