detailed solution

Correct option is A

• Concept: From the hint given to us, we all know that in West Germanic language words don't seem to be necessarily spelt the way they're pronounced. 
• A bunch of letters may well be able to convey the pronunciation of the word but they're only meaningful after they belong to the lexicon of English people language.
• Option A: Occasion belongs to English people lexicon. it's a noun which suggests an incident or an instant. Hence, we are able to say that option A is possibly the proper answer.
• Option B: Occassion doesn't belong to the English lexicon and thus, is an invalid word. Hence, we are able to say that option B isn't the right answer.
• Option C: Occation doesn't belong to nation lexicon and thus, is an invalid word. Hence, we are able to say that option C isn't the right answer.
• Option D: Occasoin doesn't belong to the English lexicon and thus, is an invalid word. Hence, we will say that option D isn't the proper answer.
• Henc⁠⁠⁠e option A is the correct answer.
• Note: it's to be noted that one often confuses between occasion which is that the correct spelling and occassion which is that the incorrect spelling.