I'm guessing 'n' because it's a common consonant in English. Looking at the pattern "_a_a___", this could be a word like "banana" or similar. The letter 'n' frequently appears in words with repeated 'a' vowels. Since common vowel 'e' was already guessed and wasn't found, and we have two 'a's, guessing other common consonants like 'n' gives us a good chance to reveal more letters.