The relationship between the weight of a package, in ounces, and the cost to mail the package can be represented by a linear function. It costs $5.90 to mail a 16-ounce package.
It costs $6.80 to mail a 22-ounce package.
Which statement is the best interpretation of the slope of the graph of this function?

A
The minimum cost to mail a package is $3.50.

B
Each additional ounce of weight costs $0.31.

C
The minimum cost to mail a package is $0.15.

D
Each additional ounce of weight costs $0.15.