What diene and what dienophile should be used to synthesize

What diene and what dienophile should be used to synthesize the following compounds?
a.
What diene and what dienophile should be used to synthesize

b.

What diene and what dienophile should be used to synthesize

c.

What diene and what dienophile should be used to synthesize

d.

What diene and what dienophile should be used to synthesize

e.

What diene and what dienophile should be used to synthesize

f.

What diene and what dienophile should be used to synthesize