I'm choosing 'r' because it's a common consonant in English words. Looking at the word pattern with 'e' in the 5th position, there's a good chance this could be a word ending with "-er" or containing "re-" patterns. Additionally, 'r' is one of the most frequent consonants in English after the ones we've already guessed. Words like "another", "charter", "counter" etc. fit this pattern and contain 'r'.