Explanation:

According to the Census 2011, Bihar had the lowest literacy rate among all Indian states, with a rate of approximately $61.8\%$. This figure was significantly lower than the national average of $74.04\%$. Option A, Rajasthan, had a literacy rate of about $66.1\%$. Option B, Jharkhand, recorded a literacy rate of around $66.4\%$. Option C, Chhattisgarh, had a literacy rate of approximately $70.3\%$. Therefore, Bihar stands out as having the lowest literacy rate among the given options and nationally in 2011.