Correct Answer: (a) Ser, Jarga, Sajjangarh, Taragarh
Solution:The height wise sequence of peaks of Aravalli mountain range situated in Rajasthan is as follow : Guru Shikhar (1722 meter), Ser (1597 meter), Jarga (1431 meter), Achalgarh (1380 meter), Raghunathgarh (1055 meter), Sajjangarh (938 meter), Khoh (920 meter) and Taragarh (863 meter). Thus, option (a) is correct.