Answer:
The virus envelope came from the monkey's cells membrane.
Step-by-step explanation:
Some virus has its viral genome packaged in a protein structure called capsid. This capsid in some virus is usually surrounded by a lipid bilayer that came from the host cells. As virus needs host cells for their reproduction, when the viral particles are ready to leave the host cell, this viral particles pass through the cell membrane (which is composed of a bilayer of lipids, proteins and carbohydrates) and takes with them part of this membrane. For this reason, is commonly found non-viral molecules in the virus that come from the host.