During eleventh Antarctic Expedition in Nov. 1991/March 1992 ____ was installed.

Second Permanent Station 'Maitree'
First permanent station 'Dakshin Gangotri'
SODAR (Sonic Detection And Ranging)
None of the above

The correct answer is: C. SODAR (Sonic Detection And Ranging)

SODAR (Sonic Detection And Ranging) is an instrument that uses sound waves to measure the atmosphere. It was installed during the eleventh Indian Antarctic Expedition in Nov. 1991/March 1992.

A. Second Permanent Station ‘Maitree’ was installed during the 13th Indian Antarctic Expedition in 1997.

B. First permanent station ‘Dakshin Gangotri’ was installed during the 5th Indian Antarctic Expedition in 1983.

D. None of the above is incorrect.