The correct option is C They are around 18% to 20% in Indian population.
Scheduled caste is a name given to the low caste people (following varna and Old Hindu caste system), which are considered inferior and untouchables in all terms. They have been given special status in the constitution of India which allows for the advancement and upliftment of these catses. According to 2011 Census, The Scheduled castes comprised of about 20 percent of total population in India.