Answer: 4
Explanation:
All non-zero integers are significant.
Any zero BETWEEN two non-zero integers are significant
Any LEADING zeros are insignificant. For example, 0.004, there is only 1 significant figure. The three zeros in front of the 4 are insignificant.
TRAILING zeros are only significant if there is a decimal point. For example:
2,569 has four significant figures but if it said 2,569.0, there would be five significant figures.