John is buying pots for the plants in his garden. The small pots are priced at m dollars each. He has already spent b dollars on the big pots. The following expression represents the total amount that John would spend on pots after buying x small pots. If the value of the small pots, m dollars, is tripled, select the statement that accurately describes its effect on the expression.

Which of the following statements is true? a. the irrational number system is not closed under multiplication, because the product of two irrational numbers is always a rational number. b. the irrational number system is not closed under multiplication, because the product of two irrational numbers is not always an irrational number. c. the irrational number system is closed under multiplication, because the product of two irrational numbers is always an irrational number. d. the irrational number system is closed under multiplication, because the product of two irrational numbers is always a rational numbers. reset submit