Answer: Option D is the correct answer.
Explanation:
No other company makes instant cameras.
A patent gives a company the exclusive right to manufacture and sell the patented product or process for a specific period of time. By patenting instant cameras, Polaroid ensures that no other company can manufacture or sell them without Polaroid's permission or without violating their patent.
Option A is incorrect because having a patent on instant cameras does not give Polaroid the right to stop other companies from using their name for other types of camera. Option B is a mistake because Polaroid's patent on instant cameras prevents other companies from making instant cameras, regardless of the name they use. It is incorrect to choose option C because instant cameras are not protected by patents, so other companies can make them as well.