In which Vedic text the term ‘Varna’ is found referred for the first time?

Which of the following Gods is referred to as 'Ritasya Gopa' in the Rigveda?

Which of the following is the correct order of the Vedic literature?

Which one of the following is oldest Veda :

The terms used for cereals in the Rig Veda are:

Which one of the following is not related to the Rigvedic period?