**The correct option (a) 0.94 **

**Explanation:**

P(A) = (50/100) = (5/10), P(B) = (60/100) = (6/10) and P(C) = (70/100) = (7/10)

A, B, C are independent events.

∴ P(A ∪ B ∪ C) = 1 – P(A ∪ B ∪ C)'

= 1 – P(A') ∙ P(B') ∙ P(C')

= 1 – [(5/10)(4/10)(3/10)]

= 1 – (6/100)

= 0.94.