Final answer:
The given information does not provide any details on the budget or optional expenses, so the question cannot be answered accurately.
Step-by-step explanation:
According to the information provided, there is no specific mention of a budget or any details about optional expenses. Therefore, we cannot determine how much money is going toward optional expenses from the given options (a.$70, b.$75, c.$10, d.$35). Without further context or information, it is not possible to answer this question accurately.