Check the solution of all options
First option
p + 2 1/2 = 5
p = 5 - 2 1/2
p = 5 - 5/2
p = 10/2 - 5/2
p = 5/2
p = 2 1/2
Second option
2 + p = 2 1/2
p = 2 1/2 - 2
p = 1/2
Third option
p - 2 1/2 = 5
p = 5 + 2 1/2
p = 7 1/2
Fourth option
4 - p = 2 1/2
-p = 2 1/2 - 4
-p = 5/2 - 4
-p = 5/2 - 8/2
-p = -3/2
p = 3/2
p = 1 1/2
The equation that has p = 2 1/2 as its solution is first option