How can the concept of a tangent line be used to explain the slope of a curve at a point?

• A. The tangent line is always perpendicular to the curve.
• B. The tangent line provides a linear approximation of the curve at that point.
• C. The tangent line is always parallel to the curve.
• D. The tangent line is irrelevant to the slope of the curve.

Answer: (B)