The correct answer is: None of these.
Panaji was founded by the Portuguese in the 16th century. It was originally called Panajim, which is a Portuguese corruption of the Konkani name Panaji. The city was the capital of the Portuguese colony of Goa until 1961, when India annexed Goa. Panaji is now the capital of the Indian state of Goa.
A. K. P. Candeth was a freedom fighter and politician from Goa. He was the first Chief Minister of Goa after it was annexed by India in 1961.
B. M. R. Sachdev is a retired Indian Administrative Service officer. He served as the Governor of Goa from 2004 to 2008.
C. Shasthadeva was a Hindu saint and philosopher who lived in the 13th century. He is considered to be one of the founders of the Shaiva Siddhanta philosophy.
None of these people discovered Panaji.