Suppose one transition rule of some PDA P is (q,0,X) = {(p,YZ), (r,XY)}. If we convert PDA P to an equivalent context-free grammar G in the manner described in Section 6.3.2 (p. 247), which of the following could be a production of G derived from this transition rule? You may assume s and t are states of P, as well as p, q, and r. a) [qXs] 0[qXt][tYr] b) [qXs] 0[rXt][tYs] c) [qXs] [pYt][tZs] d) [qXs] [rXt][tYs]