how to audit if person is exempt under section 10(26)

I think eventhough the Income is exempt u/s 10(26) for sheduled tribe of Arunachal Pradesh, Section 44AB is attracted based on the turnover criteria i.e. turnover exceeds 1 Crore.

However, the same condition not applicable to Agricultural income since the same does not enter the heads of income.

Is contract income not a business income? If Yes. Then Tax audit is necessary.

If No. Then in that case need not go for Tax audit u/s 44AB.