Final answer:
Without information on the transactions that led to the expressions, we cannot determine which expression correctly represents the amount of money left in the student's account. Generally, to calculate the remaining balance, we start with the initial amount, add any deposits, and subtract withdrawals.
Step-by-step explanation:
To determine the amount of money left in the student's account, we must identify the correct expression that reflects the transactions made. Since we only have the expressions and no content about what transactions were made, we cannot confidently select one of the options (A to D) as the correct answer. However, the general principle for calculating the remaining amount in an account is to start with the initial balance, add any deposits, and subtract any expenditures or withdrawals.
For example, if we start with $78, add a deposit of $50, and then subtract a withdrawal of $27, the expression would be $78 + $50 - $27. On the other hand, if three separate transactions were all withdrawals, the expression would be $78 - $50 - $27.
Without the specific details of the transactions, this principle gives us a guide but cannot conclude the correct answer from the provided options.