Which of the following inputs is used in software cost estimation models?
Software cost estimation models, such as COCOMO (Constructive Cost Model), commonly use 'Lines of Code (LOC)' as a primary input. LOC is a measure of the size of a software program by counting the number of lines in the source code. This metric is essential for estimating the amount of effort and time required to develop the software. Other inputs may include function points and other metrics, but LOC remains a fundamental component in many models. Reference: Barry W. Boehm's 'Software Engineering Economics'.