The function h satisfies x→−1−limh(x)=4, x→−1+limh(x)=2, and h(−1)=4. Which of the following is correct?
a) x→−1limh(x) exists and equals 4, and h is continuous at x=−1
b) x→−1limh(x) does not exist and h is discontinuous at x=−1
c) x→−1limh(x) exists and equals 2, but h is discontinuous at x=−1
d) x→−1limh(x) exists and equals 3, and h is discontinuous at x=−1