To answer this question, let's go through each option and determine who was nominated by Gandhiji to lead the satyagrahis on the Dandi March in the event of his arrest:
Option A) Jawaharlal Nehru - This option is incorrect because Jawaharlal Nehru was not nominated by Gandhiji to lead the satyagrahis on the Dandi March.
Option B) Vithalbhai Patel - This option is incorrect because Vithalbhai Patel was not nominated by Gandhiji to lead the satyagrahis on the Dandi March.
Option C) Abdul Gaffar Khan - This option is incorrect because Abdul Gaffar Khan was not nominated by Gandhiji to lead the satyagrahis on the Dandi March.
Option D) Abbas Tyabji - This option is correct because Abbas Tyabji was nominated by Gandhiji to lead the satyagrahis on the Dandi March in the event of his arrest.
The correct answer is option D. Abbas Tyabji was nominated by Gandhiji to lead the satyagrahis on the Dandi March in the event of his arrest.