How many syllables are in the infection?

Answer 1

If you are asking how many syllables are in the term "the infection", then the answer is four. "The" has one syllable, and "infection" has three: In-FEC-shun.

If you want the exact answer, we'd need to know which infection you are asking about. And even then, there are no syllables in any infection: just bacteria and blood and gunky stuff like that. "The" is a definite article, which means you are asking about a single specific infection.