You must solve for p, in order to solve for p you must move all the terms to equal p, so the equation is

first move the 2m, subtract the 2m from both sides

the 2m and -2m cancel out and now your equation looks like

now to leave p by itself you must divide by 2 on both sides as the 2 is being multiplies on the p (opposite)

now to put the answer is simplest form your answer is

which is the first answer choice