The following sources include data collection at the household level:
- Census: It collects detailed demographic, social, and economic data at the household level.
- National Family Health Survey (NFHS): It collects household-level data on health, nutrition, family planning, and other indicators.
- National Sample Survey (NSS): It collects socio-economic data at the household level on topics such as employment, expenditure, and education.
Hospital records, on the other hand, pertain to individual patients and are not collected at the household level. Therefore, the correct answer is (A), (B), and (D) only.