Select the most appropriate option to fill in the blank No. 5.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1, i.e., against.
Blank 5 Word Type: Preposition
Explanation: The correct phrase is "vaccinated against [a disease]". This is the standard preposition used in medical contexts.
Against is used to indicate protection from something – correct here.
Through, on, and across are incorrect and do not fit with "vaccinated".
Correct Sentence: ...vaccinated against yellow fever...
Conclusion: The correct option is against.