We're given all the information necessary to calculate the total costs and the total revenues. Total cost is:
600 + 0.5p
and p = 1,500, so:
cost = 600 + 0.5(1500) = 600 + 750 = $1,350
Revenue is 1,500 people times $2 each, or $3,000.
The difference is:
$3,000 - $1,350 = $1,650, choice (C).