Answer:
Let's write the costs for each option:
Option A: $10 fee for the day, plus $0.50 per mile driven.
Then if you drive x miles, the cost will be:
Ca(x) = $10 + $0.50*x
Option B: this is a fixed $27.50
Cb(x) = $27.50
(notice that cost b does not depend on x)
Now we can find the value of x such that bot costs are equal:
Cb(x) = Ca(x)
$27.50 = $10 + $0.50*x
$27.50 - $10 = $0.50*x
$17.50/$0.50 = x
35 = x
Then if you drive exactly 35 miles, the cost of both options will be the same ($27.50).
Now, if you drive less than 35 miles, the option A wil be cheaper, because the y-intercept is smaller.
If you drive more than 35 miles, option B will be cheaper, because the slope is smaller.
Then the solution is:
Option B is cheaper for more than 35 miles (and the same for exactly 35 miles)
So the correct option is option B, for x > 35 miles, option B is cheaper.
(in the options there is the notation B(s) > 35) i interpret that this means "more than 35 miles"