Which statement correctly doubles the value stored in an integer variable named answer?

The statement that correctly doubles the value stored in the integer variable named "answer" is achieved by multiplying the current value of "answer" by 2. This method directly carries out the mathematical operation necessary to double the value, ensuring that the original value is multiplied by two and subsequently assigned back to the variable.

While other options may seem plausible, they do not effectively accomplish the task of doubling the value. For instance, using "2 * answer" would indeed produce a doubled value, but it replaces "answer" in a potentially less intuitive way and does not demonstrate the common practice of multiplication assignment. The expression "answer + answer" also results in double the value, but it is less efficient than direct multiplication since it involves an extra operation of addition. Lastly, the option of "answer *= answer" is incorrect because it squares the value instead of doubling it, which significantly alters the outcome.

Thus, option C is the most straightforward and efficient way to double the value in the variable.