For :

U= {a,b,c,d,e,f,g}
A= {f,g}
B= {}
C= {a,c,e}
Identify the following sets:
_ _ _ _
a. A b. B c. C d.U

Please retype what sets you want us to identify. The line over the letters means the complement of (everything that is NOT in that set but is in the Universal). If you retype it so that it's more clear, I can help you.