What is the ultraviolet catastrophe?

The ultraviolet catastrophe was the prediction of late 19th century/early 20th century classical physics that an ideal black body (also blackbody) at thermal equilibrium will emit radiation in all frequency ranges, emitting more energy as the frequency increases.

The correction of Carlotta's vision is by using a converging lens, to fix her farsightedness.

Explanation :

Carlotta notices that the words of a book are blurry, but a sign across the road is not. She is suffering from hypermetropia. In this type of defect, the near object seems blurred and the far objects seem normal.

Hypermetropia is the defect in which image is formed behind the retina. It is also known as farsightedness. It can be corrected by using a convex lens.

So, the correct option is (c) " a converging lens, to fix her farsightedness ".