Final answer:
The domain of the function representing Ms. Curd's spending on cat toys for Theo is all values between $0 and $20.00, as spending can range from no expenditure to the maximum budget available.
Step-by-step explanation:
The domain of a function refers to the set of all possible input values (typically represented as x) for which the function is defined. In the context of Ms. Curd's spending on cat toys for Theo, the domain is limited by how much money can actually be spent. Since you cannot spend negative amounts of money, the domain cannot include negative numbers, and spending will have an upper bound based on the budget or available funds. Given the information provided, the domain of the function representing Ms. Curd's spending on cat toys would be all amounts of money from $0 to $20, so the answer would be Values between $0 and $20.00. This makes sense since she may decide not to spend any money (which would be $0) up to a maximum of $20, included in the domain because spending the entire amount is a possibility.