Suppose that the random variable ( x ) has the distribution function given by: 
[ F(x) = 
beginarray/ll 
0 & if x < -1 
1/4 & if -1 ≤ x < 1 
1/2 & if 1 ≤ x < 3 
3/4 & if 3 ≤ x < 5 
1 & if x ≥ 5 
endarray 
. 
] 
Find: 
[ P(x ≤ 1) = ______ ] 
a) 0.25 
b) 0.50 
c) 0.75 
d) 0.125