query about capital gain

x & sons,HUF , pur a land for 120000 in the p.y. 2002-03. in the P.Y. 2006-07, a partition takes place when mr. A ,a coparcener , is allotted this plot. And plot was sold in 2017-18

CA study mat. Use cost inflation index of P.Y 2006-07

And there is a NOTE  after answer is

Note- As per the view expressed by bombay HIGH Court in CIT v. MANJULA J. SHAH
in case the cost of acquisition of the capital assets in the hands of the assessee is taken to be cost of such assets in the hands of the previous owner &
the indexation benefit would be available from the year in which the capital assets is acquired by the previous owner . if this view is considered the index cost of acq. would have to be calculated by considering the cost inflation index of F.Y. 2002-03

My que is that p.y. 2002-03 ka index use karna chahiye tha

Which index year would be use