Final answer:
The pivot column in linear algebra is identified as the leftmost column with a leading entry, which is the first nonzero number from left to right in a row. This concept is separate from the significance of leading zeros in scientific measurements, which are not significant.
Step-by-step explanation:
The question refers to identifying the pivot column in the context of linear algebra, specifically when reducing a matrix to row echelon form. The correct answer to how you determine the pivot column is B. It is the leftmost column with a leading entry.
When performing row operations to simplify a matrix, the pivot column is the one that contains the leading coefficient (also known as the leading entry) in the row. The leading coefficient is the first nonzero number in a row from left to right. The procedure typically involves arranging the rows such that each leading entry is to the right of the leading entry in the row above it, which means that all nonzero rows have a pivot column, and each pivot column occurs to the right of the pivot columns in the rows above.
Regarding significant figures and zeros, the term 'pivot' in this mathematical context is unrelated to the concepts of significant digits and leading zeros in scientific measurements. However, it's worth noting that the leading zeros mentioned in the provided information are those that appear in front of all the nonzero digits, and indeed, they are never significant in measurements.