Number of piles required to support a column, is

ANS:C - 3

I worked at a project of Building where frictional piles are given in design. Isolated pile cap with one pile also given in Design. It's depending structural design. Then the pile required support of column more than one. Actually, as per theory is there is a chance of eccentricity of load upon pile cap minimum no. of piles to be used is 3 (in a triangle shape).