Determine where the given function is concave up and where it is concave down. Also find all inflection points.
q(x)=3x³+2x+8
a. Concave up on (0,[infinity]), concave down on (-[infinity],0); inflection point (0,8)
b. Concave up on (-[infinity],0), concave down on (0,[infinity]); inflection point (0,8)
c. Concave down for all x; no inflection points
d. Concave up for all x; no inflection points