Which of the following are like terms?

⇒ Like term are the terms which have same variable and powers. The coefficients need not to be matched.

⇒ Here -5xyz² and 7xyz² have same variables and same powers.

∴ - 5xyz² and 7xyz² are like terms.

Option (a) does not match to our solution.

Option (b) does match to our solution.

Option (c) does not match to our solution.

Option (d) does not match to our solution.

So, option (b) is correct answer.