तंत्रिका तंत्र को प्रभावित करने वाला बेरीबेरी रोग किस विटामिन की कमी से होता है?

Pernicious anemia is caused by the deficiency of which vitamin?

The disease 'Rickets' is caused by the deficiency of:

Night blindness is caused by the deficiency of which vitamin?