Which one of the following is a null set?A = {x : x is prime}B = {x : x + 8 = 8}C = {x : x2 + 1 = 0, x is a real number}D = {x : x2 = 4, x is an integer}

Which one of the following is a null set?A = {x : x is prime}B = {x :

1.	Which one of the following is a null set?A = {x : x is prime}B = {x : x + 8 = 8}C = {x : x2 + 1 = 0, x is a real number}D = {x : x2 = 4, x is an integer}
A.	C
B.	D
C.	A
D.	B
Answer» B. D