The hymns of Rigveda were sung in which of the following tones?

The correct answer is D. All of these.

The Rigveda is the oldest Veda, a sacred Hindu text. It is a collection of Vedic Sanskrit hymns, which were sung in three tones: udatta, anudatta, and svarita.

Uddatta is the high tone, anudatta is the low tone, and svarita is the rising tone. These tones are used to create a sense of rhythm and melody in the hymns.

The Rigveda is a very important text in Hinduism, and its hymns are still sung today. The tones of the hymns are said to have a powerful effect on the mind and soul.