Which of the following is the SI unit for length?

• A. foot
• B. inch
• C. centimeter
• D. meter

Answer: (D)

Verified step by step guidance

1. Understand that the International System of Units (SI) is the modern form of the metric system and is the standard for scientific measurements worldwide.
2. Recall that the SI base unit for length is the 'meter', which is defined based on the distance light travels in a vacuum in a specific fraction of a second.
3. Recognize that 'foot' and 'inch' are units of length used primarily in the imperial system, not the SI system.
4. Note that 'centimeter' is a metric unit of length but is a derived unit, equal to one hundredth of a meter, so it is not the base SI unit.
5. Conclude that among the options given, 'meter' is the correct SI base unit for length.