Respuesta :
Answer:
D. explain
Explanation:
if you open a mathematics reader then before exercise the first explain with examples then comes exercise .
					                   D. to explain 
the reason why it’s explain is because it’s explaining why a math problem is the way it is.
					                
					             the reason why it’s explain is because it’s explaining why a math problem is the way it is.
 
			                   
					                  