Our tour of the tower came to an end all … soon.

Analyze the question: We need a word that fits the phrase "came to an end all ....... soon." This is a fixed expression in English.

Explain the concept: The idiom "all too + adjective/adverb" means "much more than is desirable; regrettably." For example:

• "The holidays ended all too soon."
• "It was all too easy to make a mistake."

It expresses that something happened sooner (or more easily) than one would have liked.

Step-by-step solution:

• A. much: "all much soon" is ungrammatical.
• B. rather: "all rather soon" is not a natural English phrase. "Rather" can modify "soon" by itself ("rather soon"), but it does not combine with "all."
• C. too: "all too soon" is the correct idiom. It fits the meaning perfectly: the tour ended sooner than the speakers wanted, which suggests they enjoyed it.
• D. more: "all more soon" makes no sense grammatically.

The correct sentence is: Our tour of the tower came to an end all too soon.

Tip: Memorize common "all too" collocations: all too soon, all too often, all too easy, all too well. In WASSCE and JAMB lexis-and-structure questions, idioms are tested often, so learning them as fixed chunks saves time.