The correct option is C was taken
Here, 'was taken' in simple past tense is correct because it indicates
an action that has already been completed. Here, step (in the past) was taken to maintain peace and order in the district.
'Has been taken' in present perfect continuous tense is
incorrect because it is used to indicate an action that started at some point
in the past and may or may not be complete.
'Will be taken' in future continuous tense is incorrect
because it indicates what will be going on in the near future.
'Was being taken' in present continuous is
incorrect because it implies an action going on at the time of speaking.