If ( a ⋅ b ⋅ c = 0 ) and ( |a| = 3, |b| = 5, |c| = 7 ), then:
a) ( a + b + c = 0 )
b) ( a - b - c = 0 )
c) ( a × b × c = 0 )
d) ( a ⋅ b = 0 )