To calculate Connor's total cost for a movie ticket that costs \( t \) dollars with a 15% amusement tax, you must first determine the amount of tax added to the ticket price.
The tax amount can be calculated as \( t \times 0.15 \). Thus, the total cost expression would be:
\[ t + (t \times 0.15) \]
So the correct expression in terms of \( t \) that shows his total cost is:
t + (t x 0.15).