<em>I think the answer is D. They're linked to age-old efforts to use cut flowers and decorative plants in creative and expressive ways. I'm taking this exam right now.</em>
For this case we have that by definition, a linear function is of the form 
If we have that a and b are linear functions, then they are of the form:

If we multiply them we have: (Applying distributive property)

That is, we get a quadratic function.
Answer:
