Final answer:
The measurement 34.000 m has five significant digits because all non-zero digits and zeros to the right of the decimal that come after a significant digit are considered significant.
Step-by-step explanation:
In the measurement 34.000 m, there are five significant digits. All nonzero digits are always significant. Additionally, any zeros between significant digits and any zeros to the right of both the decimal point and another significant digit are also significant. In this case, the zeros after the decimal point are significant because they indicate the precision of the measurement. Therefore, the correct answer is (d) 5 significant digits.