Answer:
Option C. 
Step-by-step explanation:
we know that
If a system of two linear equations has an infinite number of solutions, then both equations must be identical
The given equation is

<u><em>Verify each case</em></u>
Option A. we have

apply distributive property

Compare with the given equation

Option B. we have

remove the parenthesis

Compare with the given equation

Option C. we have

apply distributive property

Compare with the given equation

therefore
This equation with the given equation form a system that has an infinite number of solutions
Option D. we have

Compare with the given equation
