a,b and c are projections of AB on x,y and z respectively Projection of AB on xy-plane =√a2+b2=√15 Projection of AB on yz-plane =√b2+c2=√46 Projection of AB on zx-plane =√c2+a2=7 ∴a2+b2=15,b2+c2=46,c2+a2=49 On solving a=3,b=√6,c=√40 Projection of AB on Y-axis =b=√6 no option matches