You meanrevolvingthe region around each of those 4 lines.

Unfortunately, there are many different ways to do that and you don't say which way you are practicing. I would recommend the "disk" method for (a) and (c) and the "washer" method for (b) and (d). What do you know about those methods?

In (a), where the axis is horizontal you will be integrating with respect to x. In the others the axis is vertical and you will be integrating with respect to y.