If the annual rate of simple interest increases from 15% to \(\frac{{39}}{2}\% \), a man’s interst increased by Rs. 8,100 for that year. His principal (in Rs) is:

• A. Rs. 1,80,000
• B. Rs. 1,50,000
• C. Rs. 1,85,000
• D. Rs. 1,45,000