The Aryans measured their wealth in cattle (cows), is the right answer.
To prospered their economy Indo- Aryans raised cows, goats, sheep and other animals. The most important indicator of wealth in the Aryan society was the figure of cattle a person owned. The numbers of cattle even represented the status of a family and a tribe. Eventually, cattle became so important in the Aryan community that they prohibited the killing of cattle.