Category of gst

Company is selling single units under row housing to customers Company will sign single agreement with the customer that company will first sell the plot to customer and get the registry done in the name of prospective customer and once the Registry will be done in the name of customer, the construction activities on the same registered plot will begin. Sequence of activities: Company will sign one agreement for sale of plot and construction of house on same plot. On receipt of full amount toward cost of land, the registry of plot will be done and Title of land to prospective customer will be transferred. After registry of plot and transfer of title to customer, the construction activities on plot will begin. Whether plot cost on which registry will be done and title will be transferred to customer is exempt as sale of plot. i.e Rs 15 lac will be exempt under sale of land? 2. Whether construction cost (composite work Contract) which will be done after registry of plot is taxable under work contract. i.e Rs 25 lac will be taxable under work contract? And at what rate ? 3. Whether whole cost (construction cost +Land cost) will be taxable under sale of residential unit irrespective of whether registry of complete house will be done or merely a registry of plot will be done. i.e Rs 40 lac will be taxable under Residential unit ?And at what rate? 4. Whether GST rates under PMAY is applicable if one unit will be classified under two category as mentioned above i.e part as Sale of plot and part as work contract . ie Whether GST rates under PMAY is applicable if service is classified under work contract