opportunist is the best answer! :)
Answer is: D. Opportunistic
The question states based on its "structure" opportunistic has the word "opportunity" in it and when you have an opportunity it means you have a chance to take advantage of the situation. The part of the word that is "istic" simply is put at the end of a word to tell you that it is used to describe someone. Hope this helped!
The correct answer is option D "opportunistic"
The word "opportunistic" means taking advantages of immediate opportunities usually when they are not planned.
The word "proactive" on the other hand means taking action in order to produce a change instead of waiting for something to occur.
Disdainfull means showing no respect and credulous means to believe in something that you are told without analyzing if it is true or not.