Which of the following is the SI base unit for measuring mass?

• A. gram
• B. ounce
• C. pound
• D. kilogram

Answer: (D)

Verified step by step guidance

1. Understand that the International System of Units (SI) defines standard units for various physical quantities, including mass.
2. Recall that the SI base unit for mass is the kilogram, which is the only SI base unit with a prefix (kilo-).
3. Recognize that the gram, ounce, and pound are units of mass but are not SI base units: the gram is a derived unit (1 kilogram = 1000 grams), and ounce and pound are customary units used mainly in the US.
4. Confirm that the kilogram is the fundamental SI base unit used worldwide for measuring mass in scientific contexts.
5. Therefore, identify the kilogram as the correct SI base unit for mass among the given options.