Which of the following factors made the kingdom of Avanti, the most serious competitor of Magadha?   1. Availability of Iron ore mines. 2. Fertile lands in the Ganga doab. 3. Revenue from tolls levied on the movement of goods through the silk route. Select the correct answer using the code given below.

Avanti was an ancient Indian Mahajanapada, roughly corresponded to the present day Malwa region.  Iron mines are also found in eastern Madhya Pradesh and were not far from the kingdom of Avanti  with capital at Ujjain. • Around 500 B.C., Iron was certainly forged and smelted in Ujjain, and probably the smiths  manufactured good quality weapons. • On account of this Avanti proved to be a strong competitor and rival of Magadha for almost 100  years until it was destructed by Magadha under Sisunagas.