Answer:
D. infinitely many solutions
Explanation:
to find how many solutions the equation have, we can solve it
here's the given equation: 
2(2x-3)+6=4x
our goal is to isolate the variable onto one side 
do the distributive property shown in the equation (multiply both 2x and -3 by 2) 
4x-6+6=4x
combine like terms (add -6 and 6)
4x=4x
subtract 4x from both sides, as we still have the variable on both sides 
0=0
0 is always equal to 0; that's an identity 
if we get to a point in an equation where we get an identity as the answer (ex. 3=3 or in this case, 0=0), the answer is all real numbers, or infinitely many solutions