\(P\) 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