Sec 54

Can you Please guide me,

I hold three residential flat, what will be the implication if i sell one residential flat and invest full money received from it to purchase ready property - will sec 54 allow me to get the exemption or i have to pay LTCG on sold property - as I hold more than 1 residencial falt on date of transfer .. what ever is the answer if possible please share the link too about any case study ..

because at no of place i googled but could not understand restiction of one residential property is for sec 54 or sec 54F after FY15-16

even income tax act doesnt state expection to rule as per the link 

https://www.incometaxindia.gov.in/_layouts/15/dit/Pages/viewer.aspx?grp=Act&cname=CMSID&cval=102120000000063846&searchFilter=[{%22CrawledPropertyKey%22:1,%22Value%22:%22Act%22,%22SearchOperand%22:2},{%22CrawledPropertyKey%22:0,%22Value%22:%22Income-tax%20Act,%201961%22,%22SearchOperand%22:2},{%22CrawledPropertyKey%22:29,%22Value%22:%222017%22,%22SearchOperand%22:2}]&k=&IsDlg=0 

thanks.