A. 2021 PJ1
B. 2021 AJ193
C. 2021 AFK
D. 2021 TJY
Explanation:
Recently, the observatory-cum-laboratory tracked the 1000th near-earth asteroid (NEA), named ‘2021 PJ1,’ as it passed Earth at a distance of 1.7 million kilometres. The asteroid detected was small in size, making it difficult for the radar to track it.