It is possible to build a medical term using only
a. unselected a prefix
b. unselected a combining form
c. unselected a suffix
d. unselected a prefix and a suffix

option B is correct

Explanation:

A combining form is somewhat different from affix and in medical language, it is the medical word part that gives a medical word its meaning. A combining form is the combination of the root with a combining vowel(a word part, usually ''o''). For instance the combining form for bone is 'oste/o' and the combining form of white is 'leuko'

Combining forms are used in the formation of new words, also to connect two word roots . A combining form can not stand alone as a word. So, in order to build a medical term one must join the suffix with the combining form.

transportation i would say maybe sorry it its not correct