To answer this question, we need to understand the post-increment operator (++).
The post-increment operator (++), when used after a variable, increments the value of the variable by 1 after the current expression is evaluated.
In this case, "a++" is the same as "a=a+1".
Let's go through each option to understand why it is correct or incorrect:
Option A) a=a+2; - This option is incorrect because it increments the value of 'a' by 2, not 1.
Option B) a=a+3; - This option is incorrect because it increments the value of 'a' by 3, not 1.
Option C) a=a+1; - This option is correct because it increments the value of 'a' by 1, which is the same as "a++".
Option D) a=a+4; - This option is incorrect because it increments the value of 'a' by 4, not 1.
The correct answer is option C. This option is correct because "a++" is the same as "a=a+1".