With reference to the Earth's atmosphere, which one of the following statements is correct?

(a) The total amount of insolation received at the equator is roughly about 10 times of that received at the poles.
(b) Infrared rays constitute roughly two-thirds of insolation.
(c) Infrared waves are largely absorbed by water vapour that is concentrated in the lower atmosphere.
(d) Infrared waves are a part of visible spectrum of electromagnetic waves of solar radiation.

Explanation:
Examining each of the statements in relation to the Earth’s atmosphere:

(a) The total amount of insolation (incoming solar radiation) received at the equator is indeed higher than that received at the poles due to the curvature of the Earth and its axial tilt. However, stating that it is “roughly about 10 times” is a generalized statement and the actual difference varies based on the time of year and specific atmospheric conditions.

(b) Infrared rays do not constitute roughly two-thirds of insolation. The sun emits energy across a broad spectrum of wavelengths, but the majority is in the visible light spectrum, not the infrared.

(c) Infrared waves are largely absorbed by greenhouse gases, including water vapor, in the atmosphere. This is a key part of the greenhouse effect, which helps to warm the Earth. This statement is correct.

(d) Infrared waves are not part of the visible spectrum of electromagnetic waves. The visible spectrum consists of the colors we can see (red, orange, yellow, green, blue, indigo, and violet). Infrared lies just beyond the red end of the visible spectrum and is not visible to the human eye.

Given the analysis of the options, the correct answer is (c) Infrared waves are largely absorbed by water vapor in a concentrated atmosphere.