Read the passage and answer the question. Soon some idea struck her and she went to the window and hollered, ‘Roopa! Roopa! Roopa!’ After calling out for Roopa, she had a look at the things that she had brought for her. Roopa had to sit for her home science examination the next day and Tarawati had collected things like some kitchen items, a bucket, a mug and a stool that Roopa required for the practical examination. While looking at the things that she had collected for Roopa, Tarawati recalled her husband who had died a few years ago. She remembered him berating her for not treating Roopa well. ‘Roopa’s mother! Do not think only sons deserve all love and care and not daughters’. I’m determined to give Roopa good education so that she leads a happy and meaningful life. You are not educated yourself. That’s probably why you don’t want her to be educated. This is not fair on your part. You must change your views and let her grow and flower into a happy, confident individual.’ Thinking of her husband’s admonition on this account, Tarawati felt emotional. The fact of the matter was that Roopa’s parents differed on Roopa’s upbringing and fought with each other on the issue. The fight continued for days together and often it was Roopa who intervened to broker peace between them. On his death-bed too, Roopa’s father had cried and pleaded with her to treat Roopa in a nice manner. Hugging Roopa, he had told Tarawati, ‘Take care of Roopa. Give her good education and let her decide the course of her life herself.’ While recalling the interaction, tears rolled down Tarawati’s eyes. Meanwhile, the evening shadows were getting darker. Tarawati was exhausted and had a headache too. She looked at her dust-laden feet and then around the room. In order to bring some semblance of order, she forced herself to get up and get going. Then she called her daughter again, ‘Roopa! Roopa!’ In the expression 'to broker peace between them', the underlined expression 'broker' is a/an:

1. Verb
2. Noun
3. Adjective
4. Preposition