To write a conditional statement for executing some statements only if "i" is equal to 5, you need to use the correct syntax.

The correct syntax for a conditional statement in most programming languages is:

if (condition) {
    // statements to be executed if the condition is true
}

Now let's analyze each option and determine if it is the correct way to write the conditional statement:

A. if i==5 then - This option is incorrect because the syntax is incorrect. The correct syntax for the condition should be enclosed in parentheses, like if (i == 5).

B. if i=5 then - This option is incorrect because the syntax is incorrect. To check for equality, you need to use a double equals sign (==) instead of a single equals sign.

C. if (i==5) - This option is correct. It uses the correct syntax for a conditional statement. The condition i == 5 checks if the variable i is equal to 5.

D. if i=5 - This option is incorrect because the syntax is incorrect. To check for equality, you need to use a double equals sign (==) instead of a single equals sign.

Therefore, the correct option is:

The Answer is: C. if (i==5)