The correct answer is (a).
The British Commissioner of Kumaun was a position created in 1815 after the British East India Company annexed the Kumaon Kingdom. The first Commissioner was George William Traill, who served from 1815 to 1823. He was succeeded by Frederick Henry Gardiner, who served from 1823 to 1833. The third Commissioner was Andrew Ramsay, who served from 1833 to 1843. The fourth Commissioner was Henry Wyndham, who served from 1843 to 1848.
The other options are incorrect. Option (b) is incorrect because it lists Ramsay after Gardiner. Option (c) is incorrect because it lists Finlay after Traill. Option (d) is incorrect because it lists Gardiner after Traill and Lushington.