Answer:
it is C.) participle phrase
nooo I used to know the answer
Studying is when I fall asleep is an example of =>2.parallel structure.
<span>Why? "Studying is..." can be completed in one way,let us call it (a 1,a2,...) </span>
<span>(a1) ...the elementary precondition for getting any kind of a graduation." </span>
<span>(a2) not just the action of opening a book and staring at the lines,it takes much more. </span>
<span>"When I fall asleep" can be completed is different ways,let us call them (b1,2...) </span>
<span>(b1) ...is an example of a very special situation which I am are in, </span>
<span>seen under the aspect of physiological processes in my body. </span>
<span>(b2) ...is an example of an uncompleted sentence which causes irritation of </span>
<span>your dialogue partner.</span>
