The correct option is B unlike terms
Like terms:––––––––––––––
Terms that contain the same variable which is raised to the same power are like terms.
Examples: 2x3 and 5x3, 7 and 9
Unlike terms:––––––––––––––––
Two terms that differ in either the variable(s) or their corresponding exponents are unlike terms.
Examples: 4x and 7x3, x5 and y5
Remarks:––––––––––––
Two terms can either be like or unlike. They can never be both i.e like as well as unlike.