Suppose a continuous function h satisfies h(2)=−3, h(3.5)=−1, and h(5)=4. Beginning with the interval [2,5], one iteration of the bisection method is performed. Which subinterval is then guaranteed to contain a real root of h?
a) [2,3.5]
b) [3,5]
c) [3.5,5]
d) [2,3]