Perimeter = the sum of the outer sides
#1. P = (2x + 3) + (2x + 3) + (5x - 1) + (5x - 1) + (x - 7)
#2. P = 2(2x + 3) + 2(5x - 1) + (x - 7)
#3. P = 4x + 6 + 10x - 2 + x - 7
#4. P = 15x - 3
A. Correct - equivalent to #2
B. Incorrect - does not include all of the sides
C. Correct - equivalent to #1
D. Incorrect
E. Incorrect
F. Correct - equivalent to #4
Hope this helps!