This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to care for a monocular
Wipe off the lens.
A monocular has two lenses: the ocular lens (which you put up to your eye) and the objective lens. You should keep both clean to ensure maximum visibility.

Pick your answer from:
(a). Take the lens off and, using a soft cloth, wipe off all debris. If you use the objective lens, wipe the lens once it's cleaned..
(b). Cloth wipes are best for delicate, coated lenses, like those on a monocular. You can use a microfiber eyeglass cloth, a cotton ball, or a cotton rag..
(c). Wipe both lenses off with a cotton ball. Place your lens in your ocular or objective eye socket until it is completely clean..
(d). If you are unsure how to clean your ocular lens, you should contact your optometrist to see. The objective lens is the smaller lens, which you put up to your eye socket to polish..
The answer is:
(b).