Choose the most suitable option to replace the highlighted part of the sentence:
It is difficult to diagnose malaria because its first symptoms are similar to any viral fever.
Show answer & explanation
Correct answer: B
Explanation
The sentence compares 'first symptoms' (plural) to another set of symptoms ('those of...'). Therefore, the verb 'are' is correct for the plural subject 'symptoms', and 'those of' correctly refers back to the symptoms of a viral fever.