In general for complement of l(M) :
1. {w ∈ Σ* : δ*(q0,w) ∩ F = Φ) is true for NFA
2. {w ∈ Σ* : δ*(q0,w) ∉ F)) is true for DFA
For your given problem,
(a) {w ∈ Σ* : δ*(q0,w) ∩ (Q-F) ≠ Φ)} doesn't hold good for NFA
Since, statement doesn't guarantee that string doesn't reach the final state it only says that "There will be at least one such case where string will reach to non-final state" whereas
(b) {w ∈ Σ* : δ*(q0,w) ∈ (Q-F)} holds good for NFA
Since it guarantees that all the strings will reach to non-final states only !
Correct me if I am wrong.