It is an edge triggered D flip flop where X is input, Y is clock, Q is output. Is this D Flip Flop positive edge triggered or negative edge triggered?
ADD (copied from a comment): Actually I am trying to learn digital circuits. While trying to do so I got stuck in this question. I know the answer of it (it is a positive edge level triggered D Flip Flop) but I cannot understand how can somebody deduce it from this figure.