Identifying data type of a value in memory in C?

Question

How does a program/application know that the data in a memory address is of a certain data type.

For instance, suppose there is int a; and suppose variable

Answer 1

When the C program is past linking, and don't need to expose any symbols outside, this data does not exist anymore.

The data types are language-related, when the executable is ready, the language don't play a part anymore, as now it's all memory and processor.