The correct answer is 5.

Please Note:
Use inverse operations to solve the equation for a variable.

Solution:
To solve the given equation for variable b, we use inverse operations.

Given equation:
b + 5 = 10

Now, subtract 5 from both sides and simplify.

b + 5 – 5  =  10 – 5

⇒         b   =   5

So, the value of b is 5.