Which of the Vedas is divided into Black and White?

Which of the following Vedas is divided into two branches as Krishna and Shukla ?

Which one of the following is oldest Veda :

The ninth mandala of the Rig Veda is devoted wholly to:

The largest number of hymns of Rigveda is dedicated to which Vedic god?

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