When VHS VCRs Were First Introduced, Sales Were Zero

Multiple Choice

When VHS VCRs were first introduced, sales were zero. As VCRs started to catch on, sales began to increase more and more rapidly until they peaked. After the peak, sales fell when DVD players took over that market with VCR sales almost non-existent now. This pattern is

A) the research and development cycle.
B) development and implementation.
C) the product line planning and exiting cycle.
D) the introduction to decline cycle.
E) the product life cycle.