Final answer:
The sum of two odd numbers must always result in an odd number, making option (A) the correct answer to the student's question.
Step-by-step explanation:
The student's question pertains to the properties of odd and even numbers and how they behave under different arithmetic operations. An odd number always results from the sum of two odd numbers. However, when an odd number is added to an even number or when an odd number is multiplied by an even number, the result is even. The product of two even numbers is also even. Therefore, the only option that must result in an odd number is (A) The sum of an odd number and an odd number.