44AB and 44AD

Hi,
1. Whether Tax audit is applicable for persons carrying on business is based on turnover(ie.exceeding 1 crore or prescribed limit)
or
is based on profit less than 8% on turnover even if business turnover is less than 1 crore?

because, according to 44AB(e) tax audit applicable for whom 44AD(4) attracts ie. income less than 8%

2. Another query is, Whether Non availability of section 44AD due to Turnover(TO) exceed 2 crore makes the business ineligible for next 5 asst years? if No is the answer then business can avail 44AD life-time provided business declares income
>= 8% in the year in which TO is < 2Cr

3.Is Tax audit applicable for the YEAR OF OPT OUT irrespective of TO limit OR
is tax audit mandatory for ALL the succeeding five asst. year irrespective of TO limit?
kindly clarify


Thanks.