(8 )

1. All the digits that contain non-zero are significant.

2. The zeros that are written before non-zero digits are not significant.

3. While calculating significant figures we need to start from the first nonzero digit and then end at the last non-zero digit.

4. All zeroes between two non-zero digits are significant.

5. The rightmost zeros are significant when there is a decimal point in the number.

6. So here 50000.020 are significant figures.

7. So the answer is 8.

Hence, have 8 significant figures.