The correct statements about the Amaranayakas of Vijayanagara are as follows:

1. The Amaranayakas were military commanders who were given territories to govern by the Raya. This means that they were entrusted with the responsibility of governing and maintaining order in these territories.

2. In lieu of their service and also to maintain their contingents, they were paid in cash. This implies that they were financially compensated for their role as military commanders and for the upkeep of their troops.

3. They maintained stipulated contingents and elephants. This suggests that they had a specific number of troops and elephants under their command which they had to maintain.

However, the fourth statement in the given options states that they used to send tribute to the king annually and personally appeared in the royal court with gifts to express their loyalty. This statement is incorrect as it is not mentioned in the information provided.

Therefore, the correct answer is option 2, which includes statements 1, 3, and 4.