Answer:
Option B.
Explanation:
It is given that m∠AOC = 85°, m∠BOC = (2x + 10) and m∠AOB = (4x - 15)
From the picture attached, m∠AOC = m∠BOC + m∠AOB 
Now we replace the values of angles as given
85 = 2x + 10 + 4x - 15
6x - 5 = 85
6x = 85 + 5
6x = 90
x = 

x = 15 
Since m∠BOC = 2x + 10 
By replacing x = 15
m∠BOC = 2(15) + 10 
 = 30 + 10
 = 40°
And ∠AOB = 4x - 15
By replacing x = 15
∠AOB = 4(15) - 15
 = 60 - 15
 = 45°
Therefore, Option B is the answer.