A. miserliness
B. simplicity
C. purity
D. innocence
ostentation : the pretentious or showy display of wealth and luxury, designed to impress.
miserliness : excessive desire to save money; extreme meanness.
simplicity : the quality or condition of being easy to understand or do.
purity : freedom from adulteration or contamination.
innocence : the state, quality, or fact of being innocent of a crime or offence.
Antonym of ostentation is miserliness