Vital … is still spread … word of mouth in most villages in Africa?

Analyze the question: The sentence is "Vital ...... is still spread ..... word of mouth in most villages in Africa." We need a noun for the first gap and the correct preposition for the second.

Concept:

• Information is an uncountable noun, so it takes no "s" and no article. All four options use "information" correctly, so the real test is the preposition.
• The fixed expression is "by word of mouth". It means through spoken communication rather than in writing. Prepositions like "from," "with," or "through" do not fit this idiom.

Step-by-step:

1. Gap 1: "Vital information" fits in all options.
2. Gap 2: Test each preposition. • "spread from word of mouth": wrong, the idiom doesn't use "from." • "spread with word of mouth": wrong, "with" suggests accompaniment. • "spread by word of mouth": correct, this is the standard idiom. • "spread through word of mouth": this is sometimes heard in informal usage, but the established, standard idiom is "by word of mouth." It is also what the JAMB key expects.

Answer: The correct option is C. information / by.

Tip: Memorize fixed phrases with "by": by heart, by hand, by word of mouth, by chance, by air/road/sea. When an exam asks about idioms, go for the standard fixed form rather than a near-synonym.