So 5 letters needed
This question is pissing me off because its not designed well...
"or a pair of distinct letters written in alphabetical order."
That clearly means that AD, AC, cannot be used.... these are not in alphabetical order.
I got 7.
A, B, C, D, E, F, G, AB, BC, CD, DE, EF
Obviously the official answer is 5 but can someone please explain to me whe
"a pair of distinct letters written in alphabetical order" is not nullifying AC or AD.... AC is not in alphabetical order.