Detailed explanation and options for the selected question.
Jyoti Basu was the longest serving Chief Minister of India, serving for over 23 years in West Bengal. Option "P. S. Sreedharan Pillai" is incorrect as he did not serve for such a long period. Option "Sheila Dikshit" served for a long period in Delhi but not as long as Jyoti Basu. Option "M. Karunanidhi" served for multiple terms in Tamil Nadu, but his tenure was shorter than that of Jyoti Basu.