Final answer:
Optiom a) chars is correct. n the context of a switch statement, chars, ints, and enums can be used because they can be compared to integers. Doubles are not typically allowed due to precision issues.
Step-by-step explanation:
The question is regarding which data types can be used with the switch statement in programming. In many programming languages like C, C++, and Java, the switch statement is limited to types that can be checked for equality with integers. Therefore, one can use chars and ints, because they can be easily compared to integer values. However, doubles are not usually allowed because floating-point values can lead to precision issues. Finally, enums can also be used since they are internally represented as integers.
So, the expressions that can be used in a switch statement are:
chars (A)
ints (B)
enum values (D)
Doubles (C) are typically not permitted in a switch statement because of their precision and comparison complexities.