correct answer is: b) Rs 2656.25

Explanation

Here, Find the sum (principal), we can use S.I. formula.
According to the question,
Simple Interest (S.I.) = Rs 850
Rate (r) = 8 % p.a.
Time = 4 years
We know,
S.I. =\ \frac{p\ \times\ t\ \times\ r}{100}
Putting the value, we get:
850=\frac{p\times8\times4}{100}
\rightarrow32p=85000 _{[cross multiply]}
\rightarrow p=\frac{85000}{32}
\rightarrow p=2656.25
\therefore The sum of money (principal) is Rs 2656.25
Ans: The sum is Rs 2656.25, fetched a simple interest of Rs 850 at the rate of 8% per annum in 4 years.

Another way to ask this same question is:
1. What is the principal amount invested to earn a simple interest of Rs 850 over 4 years at a rate of 8% per annum?
2. Calculate the sum of money needed to produce a simple interest of Rs 850 over a 4-year period with an annual interest rate of 8%.
3. Determine the principal sum required to accrue a simple interest of Rs 850 over a 4-year period at an interest rate of 8% per annum.
4. Find out the initial amount of money invested that generates a simple interest of Rs 850 at a 8% per annum interest rate for 4 years.
5. Calculate the principal sum that yields a simple interest of Rs 850 at an annual interest rate of 8% over a period of 4 years.