Which one among the following is not true with regard to Rig Veda Samhita?
(a) There are about 300 non-Indo- **** words in Rig Veda
(b) There is a reference to dasarajna (battle of ten kings) in the Rig Veda
(c) It is mentioned in the Rig Veda that the Bharata chief Sudas fought against a confederacy of ten tribes
(d) Purus sided with Bharata in the battle of ten kings