What must define your parallel system design for this customer
a. a variety of spring flowers arranged as if they were growing in a garden.
b. an s- curve of ivy cascading below the bowl.
c. at least two parallel groups of upright flowering branches used as line materials.
d. a perfect line of massed chrysanthemums forming concentric circles of colors.

My answer is: C. At least two parallel groups of upright flowering branches used as line materials.

I based that answer from the missing data that this question had.

Oval bowl that is very large and low and has a pale gray crackled glaze. Said bowl is a bonsai container. It will be the container of the floral arrangement. 
The bowl will be placed in the foyer of his business office, on a counter that will make the bowl visible in both sides. Colors in the foyer are black, white, and gray.
Customer wants an artistic arrangement that suits the bowl

Dynamic symmetry should be the answer