2. which part of a refracting telescope forms the image?
a. convex lens
b. concave lens
c. convex mirror
d. a concave mirror

In a refracting telescope convex lens forms the image.

c. Convex mirror

Explanation:

Telescope is an instrument used for magnification of distant objects. The convex lenses objective and eyepiece are the two parts of a refracting telescope.  

Objective has a greater focal length when compared with the eyepiece. Image of a distant object is formed at the second focal point of the objective. This image is magnified by the eyepiece.  

The objective and eyepiece lenses can only produce an inverted image since they both are convex lenses. The function of producing a final erect image is performed by a pair of inverting lenses.