A. Ujjain
B. Jaipur
C. Varanasi
D. Delhi
Choose the correct answer from the options given below:
To arrange Jaisingh's observatories chronologically, we need to know the approximate establishment year for each location.
| Observatory | Location Code | Approx. Establishment Year |
| Delhi | D | 1724 |
| Ujjain | A | 1725 |
| Jaipur | B | 1734 |
| Varanasi | C | 1737 |
Therefore, the correct chronological order is Delhi, Ujjain, Jaipur, Varanasi, represented as D, A, B, C.