Each line between 0 and 1 is 1/10 ( there are 10 lines)
First arrow is on the 3rd line so would be 3/10
The next arrow is 3 away from that so would be 3/10
The 3rd arrow is 2 away from the 2nd so would be 2/10
3/10 + 3/10 + 2/10 = 8/10
The answer is b