George's Greenery Orders Two Dozen Live Dogwood Trees from Nancy's

George's Greenery orders two dozen live dogwood trees from Nancy's Nursery.George's is to keep the dogwoods healthy by keeping them in a greenouse following certain instructions to keep the air at the right temperature,etc.The sale is made on a trial basis and George's may return all unsold dogwood trees at the end of 30 days.This contract is a:

A) contract to sell future goods.
B) conditional sale.
C) sale or return.
D) sale on approval.