Sizzling Chicken Shack sells chicken wings in a variety of packages. The cost per chicken wing is the same in every package. A package of 21 wings costs $17.85. Write and solve a proportion that can be used to determine the cost of a package of 6 wings. Round the answer to the nearest hundredth if necessary.
a) $4.86
b) $5.10
c) $3.40
d) $3.95