Simplify $((5p¹)-2p⋅4)(3)(4-1÷3)(6p-9)$ to a much simpler expression of the form $ap-b$, where $a$ and $b$ are positive integers.
a) $15p - 54$
b. $15p + 54$
c. $18p - 36$
d. $18p + 36$