Answer:
The control Delicious has over the details of the work
Step-by-step explanation:
The key factor refers to the most prominent reason which proves a fact in the most convincing manner.
In the given case, Delicious coffee company has hired Elton to sell products in an area and have determined his compensation in the form of salary, commission and other benefits.
Also the terms of selling by which Elton must abide by have been mutually agreed upon between the parties.
The key factor which determines that Elton is Delicious's employee is governed by the extent of control Delicious (Employer) exercises over the details of his work i.e how the employer controls his work and tasks.
The key factor would also be reflected in Elton's acts relating to his performance of the job.