\(P\) and \(Q\) are both positive integers. When \(P\) is divided by \(Q,\) the remainder is some positive integer \(D\)

\(P\) and \(Q\) are both positive integers. When \(P\) is divided by \(Q,\) the remainder is some positive integer \(D,\) and when \(P\) is divided by \(Q + 3,\) the remainder is also \(D.\) If \(\dfrac{P}{Q} = 1020.75\) and \(\dfrac{P}{Q + 3} = 816.6,\) then which of the following gives the correct set of \(\{D, Q\}?\)

A. \(\{6, 12\}\)
B. \(\{6, 15\}\)
C. \(\{9, 12\}\)
D. \(\{9, 15\}\)
E. \(\{15, 24\}\)

[spoiler]OA=C[/spoiler]

Source: Magoosh