Capital gain nature

A person owns a plot of land since last 28 years. He enters into an agreement with a builder to develop the plot. In return, builder agrees to give 3 residential flats to the land owner as consideration. (builder intends to create an apartment of the building constructed & hence the land owner will remain the owner of part of the land)

If the land owner sells the 3 flats immediately, will it be considered Short Term Capital Gain or Long Term Capital Gain?

please suggest relevant case laws, if any..

thanks