Which property justifies this statement?

"if 2a + 3 = b and b = 7, then 2a + 3 = 7."

a.
associative

b.
symmetric

c.
distributive

d.
transitive

I believe its C because they distribute instead of reverse like A would be

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.