To answer this question, the user needs to know about the life of Mahatma Gandhi and his family.

Option A: Gauri - This option is incorrect. Gandhiji did not have a sister named Gauri.

Option B: Raliat - This option is correct. Gandhi had a sister named Raliat.

Option C: Rambha - This option is incorrect. Gandhiji did not have a sister named Rambha.

Option D: Meera - This option is incorrect. Gandhiji did not have a sister named Meera.

The Answer is: B. Raliat.