With reference to ancient India (600–322 BC), consider the following pairs : Territorial region : River flowing in the region I. Asmaka : Godavari II. Kamboja : Vipas III. Avanti : Mahanadi IV. Kosala : Sarayu How many of the pairs given above are correctly matched?

1. (a)Only one
2. (b)Only two
3. (c)Only three
4. (d)All the four