The correct option is
B to work
In order to fill in the blank with the most suitable verb, we need to understand the usage of 'make'. 'Make' means to force someone to do something. If 'make' is used in a passive (voice) sentence, we use the word 'to' along with the verb. In an active sentence, we do not use 'to' with the verb. The verbs without the marker 'to', are called bare infinitives.As the given sentence is in the passive voice, we will not use the bare infinitive here; we will use the verb with the marker 'to'.
NOTE: Here, 'made' is used as the main verb, which describes the sentence in past tense. Though the sentence is in past tense, the verb with the marker 'to' will always be in its original form.
Option B - As explained above, the verb accompanied by the marker 'to' will always be in its original form. Hence, we can't use 'to working', as the verb 'working' is the participle of the verb 'work'. Hence, option B is incorrect.
Option C - 'Work' is a verb in its original form and will be used as a bare infinitive in case of active voice only. As the sentence is in the passive voice, we can't use 'work' here. Hence, option C is incorrect.
Option D - 'Works' is the third person form of the verb 'work'. As explained above, the given sentence is in passive voice and we need the verb with the marker 'to', we can't use 'works' here. Hence, option D is incorrect.
Option A - 'To work' is an infinitive. The verb 'work' is accompanied by the marker 'to'. As the sentence is in the passive voice, we can use 'to work' here. Hence, option A is the correct answer.
'She was made to work on a Saturday night.'