Final answer:
The correct use of an apostrophe in a contraction is shown in the sentence 'The tornado's approach sent everyone running for cover.'
Step-by-step explanation:
The sentence that shows the correct use of an apostrophe in a contraction is: The tornado's approach sent everyone running for cover.
An apostrophe is used in contractions to indicate the omission of one or more letters. In the sentence, the contraction 'tornado's' is formed by combining 'tornado' and 'is' to become 'tornado's'.
Contractions are common in speech and informal writing. They are formed by adding an apostrophe to combine two words, such as 'it is' becoming 'it's' or 'they are' becoming 'they're'.