Which one of the following Brahmana texts belongs to the Rigveda?

Which one of the following is oldest Veda :

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

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

Which of the following is a characteristic of Mandala IX of the Rigveda?

The compilation of which among the following is based upon the Rig Veda?