Radhika decided to donate 18% of her monthly salary to an NGO. On the day of donation she changed her mind and donated Rs 7749 which was 82% of what she had decided earlier. How much is Radhika's monthly salary?

• A.  Rs 42800
• B.  Rs 52500
• C.  Rs 57500
• D.  Rs 56500
• E.  None of these