The - - operator Group of answer choices is a unary operator. subtracts one from the value of its operand. must have an lvalue, such as a variable, as its operand. can be used in either prefix or postfix mode. All of these are true.

The answer to this question is the "All of these are true".

Explanation:

The answer to the given question is the "All of these are true" because An operator is a symbol that operates on a value or a variable. In the programming language, there are many types of operators like Arithmetic Operator, Assignment Operators, Increment and Decrement Operator, etc. In this question we use the Increment and Decrement Operator there are two types of operator that can be given as:

Increment (i)

Pre Increment. (++i) Post Increment. (i++)

Decrement (d)

Pre Decrement. (--d) Post Decrement. (d--)

That's why the answer to this question is "All of these are true".