Three concurrent co-planar, non-collinear forces $1N, 2N$ and $3N$ acting along different directions on a body 

can keep the body in equilibrium if $2N$ and $3N$ act at right angle. 

can keep the body in equilibrium if $1N$ and $2N$ act at right angle. 

cannot keep the body in equilibrium. 

can keep the body in equilibrium if $1N$ and $3N$ act at an acute angle.