In the Late 1950s and 1960s, Television Westerns Were Extremely

In the late 1950s and 1960s, television westerns were extremely popular and included Gunsmoke, Bonanza, Wagon Train, and The Big Valley. When ratings declined as viewers' tastes changed, production companies found the networks no longer wanted to buy and televise such shows. The production companies used a(n) ________ strategy and stopped production on all television westerns when the networks stopped showing them.

A) diversification
B) aggregation
C) segmentation
D) deletion
E) harvesting