To answer this question, the user needs to know the full name of the cartoonist R.K. Laxman.
Option A is incorrect because "Kannan" is not part of R.K. Laxman's full name.
Option B is incorrect because "Krishnan" is missing the suffix "swami" from the name.
Option C is correct. The full name of R.K. Laxman is Rashipuram Krishnaswami Laxman.
Option D is incorrect because "Ranganathan" is not part of R.K. Laxman's full name.
Therefore, the answer is: C. Rashipuram Krishnaswami.