Not since Communist China crushed the democratic demonstrations at Tia

Main point is to explain that China crushed a demonstration and that was so brutal that no other country has done it again since that moment of time.

has.............is perfect to indicate present perfect tense for a task that has begun in the past at one time and has its impact till now.

did..............we cant use did as it indicates verb in past tense only.

Not since Communist China crushed the democratic demonstrations at Tianenmen Square has a country so brutally denied the right of its citizens that they could speak freely.

(A) has a country so brutally denied the right of its citizens that they could speak freely
(B) did a country so brutally deny the right of its citizens that they could speak freely
(C) has a country so brutally denied the right of its citizens to speak freely
(D) did a country so brutally deny the right of its citizens to speak freely
(E) has a country so brutally denied whether its citizens had the right that they could be speaking freely

verb denied makes sense not just deny.
denied the right to do sth is correct................filtering B and D.
not denied the right of its citizens that they could speak freely as this is cumbersome.............this filters A, B and E.
Also whether spoils the meaning in E.