A random variable X has distribution function F(t) =

⎧⎪⎨⎪⎩

0, t < −2,

(t + 2)∕8, −2 ≤ t < 1, 5∕8, 1 ≤ t < 3, 1, t ≥ 3.

Then the probability P(−1 ≤ X < 3) equals

(a) 5 8

(b) 3 8

(c) 1 2

(d) 7 8

(e) 3 4