Match the items of column P with those in columnQ.
Aa - (i), b - (ii), c - (iii), d - (iv)
Ba - (iv), b - (ii), c - (i), d - (ii)
Ca - (iii), b - (iv), c - (ii), d - (i)
Da - (ii), b - (iii), c - (i), d - (iv)
grain is separated from stalk by the process of threshing .