An enterprising businessman earns an income of ₹ 1 on the first day...

Given, income on the first day& $= ₹ 1$

Again, income on the second~day~$= ₹ 1 \times 2 = ₹ {2}^{1}$

Now, income on the third day~$= ₹ 2 \times ₹ {2}^{1}$

$= ₹ {2}^{2}$and so on.

Therefore, income on the n^th day~$= ₹ {2}^{n - 1}$

So, income on the 10^th day $= ₹ {2}^{10 - 1} = ₹ {2}^{9}$

Hence, $₹ {2}^{9}$& is the correct answer.