∫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.