Using this chart of word roots and affixes, which is the most likely meaning of the word monotone?

Prefixes Roots Suffixes mono-: one bi-: two tri-: three omni-: all pro-: for, in favor of, forward epi-: on, outside se-: apart athlon: prize, contest ped, pod: foot phon, phone: sound spect: to look derma: skin hydr: water cred: to believe, trust tone: tone, sound -able, -ible: capable of -ic: like, related to -oid: resembling -ant: having the qualities of -ia: condition, world, society -ology, -logy: the study of -ous: full of -ence: a state or condition

A. A loud, startling noise

B. A picture using only one color

C. A single, continuing sound

D. A softly spoken voice

C. is the correct​