The formula for Amount(A) is
Amount (A) = (P) Principal \(\times[1-\frac{r}{100}]^n\)
Now putting the values given in the question to the equation, we get
17640 = 16000\(\times[1-\frac{r}{100}]^2\)
On solving the equation, we get
\(r=\) 0.05 = 5\(\%\)
So, the Rate of interest = 5\(\%\) per annum
The correct option is (A)