What enables a variable-rate,multi-leaf spring to become progressively stiffer as weight is added to a frame?

A) cam brackets make contact close to the center of the spring as it deflects
B) the ends of lower leaves in the spring pack come into contact with the upper leaves
C) both A and B
D) neither A nor B

Variable-rate

A term used to describe a financial instrument or system where the interest rate can change over time based on predetermined conditions or an index.

Multi-leaf Spring

A type of suspension spring made of several layers of metal bound together to absorb shocks and support loads.

Cam Brackets

Mounting brackets used to hold and position camshafts within an engine, ensuring proper timing and operation.