Although the Supreme Court ruled as long ago as 1880 that Blacks could not be excluded outright from jury service, nearly a century of case-by-case adjudication has been necessary to develop and enforce the principle that all juries must be drawn from “a fair cross section of the community.”

A has been necessary to develop and enforce the principle that all juries must be
B was necessary for developing and enforcing the principle of all juries being
C was to be necessary in developing and enforcing the principle of all juries to be
D is necessary to develop and enforce the principle that all juries must be
E will be necessary for developing and enforcing the principle of all juries being

Edited for underline and bold.