The base quantity among the following is:
A) Speed
B) Weight
C) Length
D) Area

Hint: Length is the fundamental quantity Speed weight is not fundamental quantity. Base quantities are those which are independent of any other physical quantity.

Complete step by step solution:
A base quantity is one of a conventionally chosen subset of physical quantities, where no quantity in the subset can be expressed in terms of the others. There are seven basic fundamental quantities: Length, mass, time, electric current, amount of substance, luminous intensity and temperature.

So, the base quantity among the following is length.

Additional Information: Dimensional analysis is the practice of examining the relationship between physical quantities by identifying the dimensions of physical quantities. These dimensions are independent of numerical multiples and constants and all quantities in the world can be expressed as a function of fundamental dimensions.

Note: An expression representing the power to lift the basic units to obtain a unit of a quantity is called the dimensional formula of that quantity.