If i multiple 5460 and 12 and then divide 65520 and 54 and i get 1221 what at would be my best estimatea.500b.2500c.25000d.36000

The lengths of two sides of a triangle are 9 and 15. what can be said about the length of the third side? a. it must be greater than or equal to 6 and less than 24. b. it must be greater than or equal to 6 and at most 24. c. it must be greater than 6 and less than 24. d. it must be greater than 6 and at most 24.