Answer:
B. a conversion factor
Step-by-step explanation:
The expression "1 in. = 2.54 cm" is called a conversion factor.
With this expression inches can be converted to centimeters.
Inversely the expression can also be used to convert centimeters to inches
By rearranging the equation we get
The statement which shows the equal nature of two different expressions is called an equation
Rule of thumb is a general approximation of a result of a test or experiment.