If India were to ban the export of gold altogether, by what approximate percentage should the export of the rest of the minerals increase so that the total quantity of minerals exported remains the same?

Total quantity of gold exported by India to all six countries = 28

Total quantity of other minerals except gold exported by India to all six countries = 103+149+132+75 = 459

Here, 28 units of other minerals should be added instead of gold to the present 459 units to keep the total exported minerals same.

$$\therefore$$ Percentage increase in the export of rest of the minerals is given by,

$$\frac{28}{459}$$ x 100 = 6 (approx)

Hence, option D is the correct answer.