The correct answer is A. Jhajjar.
As per the census 2011, the SC population in Jhajjar district is 27.2%, which is the highest among all the districts of Haryana. The SC population in Mewat district is 26.2%, Panchkula district is 18.5%, and Hisar district is 18.3%.
The SC population in Haryana is 21.5%, which is higher than the national average of 16.6%. The SC population in Haryana is concentrated in the southern and western parts of the state. The districts with the highest SC population are Jhajjar, Mewat, Gurgaon, and Faridabad.
The SC population in Haryana is mainly engaged in agriculture and allied activities. The SC population in Haryana also has a significant presence in the government sector and in the private sector.
The SC population in Haryana has made significant progress in education and employment in recent years. However, the SC population in Haryana still faces many challenges, such as poverty, illiteracy, and discrimination.