A student solves the following problem:

Problem: 2(x-3) + 3x = 19

Step 1: 2x-6+3x=19
Step2: (2x+3x)-6=19
Step 3: 5x-6=19
Step 4: 5x-6+6=19+6
Step 5: 5x = 25
Step 6: x = 5
What property justifies going from step 3 to step 4?

Substitution Property
O Distributive Property
O Addition Property of Equality
O Commutative Property of Addition
O Division Property of Equality