The answer would be A.
Step-by-step explanation:
If they enter with one car, that’s a price of $3 for the car alone. Because there’s also a fee for each person who enters, and there is a family of 5 who enters, x is representative of the cost for each person who enters. Therefore, there would be 5 x’s and one 3 that when solved would add up to the total of $45 they spent. That would mean A is correct because the equation would be x + x + x + x + x + 3 = 45.