The points whose position vectors are $2 \overrightarrow {i}+3 \overrightarrow {j}+4 \overrightarrow {k},\; 3 \overrightarrow {i}+4\overrightarrow {j}+2 \overrightarrow {k}$ and $4 \overrightarrow {i}+2 \overrightarrow {j}+3 \overrightarrow {k}$ are the verticies of

Question

(a) an isosceles triangle

(b) right angled triangle

(c) equilateral triangle

(d) right angled isosceles triangle