Answer:
The answer is: Only A is correct.
Explanation:
Variables in a program can assume different values at different times, and the program can then produce different results, depending on circumstances, so A is correct.
In a computer language, a reserved word (also known as a reserved identifier) is a word that cannot be used as an identifier, such as the name of a variable, function, or label – it is "reserved from use". This is a syntactic definition, and a reserved word may have no meaning. So, B is incorrect.
Hence, the answer is: Only A is correct.
