In a purely cohesive soil, the critical centre lies at the intersection of__________.

A)
Directional angles
B)
perpendicular bisector of slope and the locus of the centre
C)
perpendicular drawn at l/3rd slope from toe and the locus of the centre
D)
perpendicular drawn at 2/3rd slope from toe and the locus of the centre

Correct Answer :   directional angles