Select the most appropriate option to substitute the underlined segment in the given sentence. If there is no need to substitute it, select No Improvement.

Amnesty International had a reputation of being a hard place to work so the word ‘toxic’ was used to describe the Amnesty work culture so far back as the 1990s.

A

No Improvement.

B

as far back the 19903

C

so far back as the 1990

D

as far back as the 1990s