When an expression containing a is part of an if statement, the assignment is illegal.
a.
greater than sign
b.
double equal sign
c.
single equal sign
d.
boolean value

single equal sign

Explanation:

The if statement is used for check the condition.

syntax:

if(condition)

{

  statement;

}

let discuss the option one by one for find the

Option a:  greater than sign

this assignment operator '>' is valid. it is used to create the condition like n>0, p>4.

Option b:  double equal sign

this assignment operator '==' is valid. it is used to check the equal condition.

like 2 == 2.

Option c:  single equal sign

this assignment operator '=' is not valid. it is used for assign the value to variable not for checking like a=2, in this 2 assign to a but it not apply the condition.

Option d:  Boolean value

we can provide the Boolean value as well if Boolean is TRUE, if condition true otherwise false.

Therefore, the option c is correct option.