We are asked to find the Moment about a point in 3-D. And we already know that:

Moment (M) = distancr(r) x Force(F)   

Bold letters represent vector quantities here and 'X' signifies cross product.

Now we are provided with F and two points in space. So to find moment about B. We first find r:

r= AB= (6i + 2j + 2k) - (8i + 1j + 4k)

  = -2i + j + 2k

So M= rx F = (-2i + j + 2k) x (80i + 50j- 60k)

                    = (-40i + 280j - 180k)