Which of the following does not show any interference pattern? a) Soap bubble b) Excessively thin film c) A thick film d) Wedge Shaped film

Which of the following does not show any interference pattern?
a) Soap bubble b) Excessively thin film c) A thick film d) Wedge Shaped film

I saw that explanation (Answer: b
Explanation: An excessively thin film shows no interference pattern because in that case, as the thickness of the film is negligible, the path difference, Δ, between the two reflected rays turns out to be λ/2 which is the condition of minima. Hence, the pattern is not observed.
The interference pattern is observed in the soap bubble, thick film, and wedge-shaped film.)
but it is n’t clear . Does anyone have another good and simple explanation ?