∫f(x) is monotonically increasing, and f(t)≤f(ms).
∴t≤ms, that is,-(2s+1) ≤ ms.
∴(m+2)s≥- 1
∵m∈
I.e. greater than 0.
∴s≥- 1/(m+2)
∴m∈[- 1, 1] substitution
Choose answer B.