The Rule for the Order of Joining Word Roots at the Beginning

The rule for the order of joining word roots at the beginning of a term is:

A) put them in alphabetic order and add combining vowels, regardless of whether the initial letter is a consonant or a vowel.
B) put them in alphabetic order and add combining vowels only if the initial letter is a vowel.
C) put them in order of the directionality of the body system and add combining vowels between each word root, regardless of whether the initial letter starts with a consonant or a vowel.
D) put them in order of the directionality of the body system and add combining vowels between the word roots only if the initial letter is a consonant.