n C$++,$ which of the following statements about overloading the comparison operator $(==)$ is true?

a$)$ Overloaded $=$ operators should return an int value.

b$)$ Overloaded $==$ operators should return a bool value.

c$)$ Overloaded $==$ operators can have any number of parameters.

d$)$ Overloaded $=$ operators cannot be declared as friend functions