Their shop stocks _____ overwhelming variety of goods.

Analyze the question: We need a word that fits before "overwhelming variety of goods." The blank comes before a singular noun phrase starting with a vowel sound ("overwhelming").

Concept: Articles and determiners.

• "A" is used before consonant sounds, and "an" before vowel sounds.
• "Variety" is a singular countable noun, so it needs a determiner such as "a/an", "the", "every", or "each" before it.
• Here, the adjective "overwhelming" comes between the determiner and the noun. Its first sound is a vowel (/oʊ/), so the article must be "an".

Check each option:

• A. any: Usually used in negatives and questions ("Does the shop stock any goods?"). It doesn't fit a positive statement like this one, and "any overwhelming variety" sounds unnatural.
• B. every: "Every overwhelming variety" would mean each and every variety is overwhelming, which doesn't make sense with "a variety of goods."
• C. an: "an overwhelming variety of goods" is grammatically correct and natural. It means a huge, almost too-large range of goods.
• D. each: "Each overwhelming variety" has the same problem as "every" and changes the meaning.

Solution: "Their shop stocks an overwhelming variety of goods."

Tip: When choosing between "a" and "an," listen to the sound of the word that follows, not just the spelling. Words starting with vowel sounds (a, e, i, o, u sounds) take "an": an overwhelming, an honest, an umbrella. Also, the phrase "a variety of" is a common collocation in WASSCE English, so watch for it.