The manager of a guitar shop plans to order some new guitars.The cost of each model T guitar is $300.The cost of each model S guitar is $500.The manager will order a minimum of 10 guitars. He can spend a maximum of $4500 on the guitars. Let t represent the number of model T guitars ordered, and s represent the number of model S guitars ordered.

Which system of inequalities represents the constraints on this order?
a. t+s≥ 10 ; 300t+500s≥ 4500
b. t+s≤ 10 ; 300t+500s≤ 4500
c. t+s≥ 10 ; 300t/ 500s≤ 4500
d. t+5≤ 10 ; 300t+500s≥ 4500