Determine where the function is concave upward and where it is concave downward.

Concave upward:
A. (-/infty,0)
B.(-1,1)
C.(0, infinity)
D. (- infinity,infinity)
E. (no interval)

Concave downward:
A.(-/infty,0)
B.(-1,1)
C.(0, infinity)
D.(- infinity,infinity)
E. no interval