"A" sounds the best and is for sure the correct answer!
Ending the adjectives with -ed is not needed, so those answers are out. As for the numbers, the rule is usually that numbers one through nine are spelled out whereas number 10 and up are written in numbers. That said, you do not hyphenate the number with the word, so four-letter word would be correct.
Its A. because -ed is past tense.
