Suppose ( {a} = (-3.45 , {m}){i} + (4.87 , {m}){j} ), ( {b} = (1.84 , {m}){i} + (-4.95 , {m}){j} + (2.2 , {m}){k} ), and ( {d} = (-4.82 , {m}){i} + (-3.61 , {m}){j} ).
a) ( {a} ⋅ {b} = 0 )
b) ( {b} ⋅ {d} = 0 )
c) ( {a} ⋅ {d} = 0 )
d) ( {a} ⋅ {b} = 1 )