Question

unwonted (adj.)
incapable of being perceived by the senses
not habitual or ordinary
affectedly refined or delicate
brought under control; made less intense

Explanation:

"Unwonted" is an adjective that describes something out of the ordinary, not customary or habitual. The other options do not match its definition: the first describes "imperceptible," the third describes "affectedly refined" (a definition for "precious" or "dainty"), and the fourth describes "tempered" or "mitigated."

Answer:

B. not habitual or ordinary