Answer:
Option (b) is correct.
The expression is equivalent, but the 
 term is not completely factored.
Explanation:
Given : a student factors 
 to 

We have to choose the correct statement about 
 from the given options.
 
Given 
 is factored to 

Consider 
 
Using algebraic identity, 

comparing 
 and b = 4, we have,

Thus, the factorization is equivalent but we can simplify it further also, as 
Using algebraic identity, 

Thus, 

Can be written as 

Thus, the expression is equivalent, but the 
 term is not completely factored.
Option (b) is correct.