Demetri has trouble spelling the word “banana.” Whenever he tries to spell the word, he writes the letters “ba,” then writes “na” one or more times, then stops. Every time Demetri writes the letters “na” there is a 60% chance that he will write the letters “na” again (otherwise he stops). When Demetri tries to spell the word “banana,” what percent of the time does Demetri spell “banana” correctly?

A. 14.4%
B. 24%
C. 36%
D. 40%
E. 60%

Answer: B

Source: Veritas Prep