If the hydrangea blooms in late summer it is a panicled hydrangea. If it is grown for florists, it is a bigleaf hydrangea. This hydrangea is grown for florists and is therefore not panicled.

The argument above relies on which of the following to reach its conclusion?

a. the panicled hydrangea has no features in common with the bigleaf hydrangea
b. if a hydrangea is panicled, it is not bigleaf
c. no bigleaf hydrangea blooms in the late summer
d. all panicled hydrangea blooms in the late summer
e. of the hydrangeas used by florists, none blooms in the late summer