The correct option is B is working
In order to find out the correct form of the verb needed, let's first understand these tenses. Present continuous tense is used to express an action that is continuing at the moment. Usually, in this case, the start time of the action isn't given. Present perfect continuous tense is used to express an action that has started in the past, continuing in the present, and might go on or end in future. Here, usually the start or the end time of the action is given. This sentence doesn't have a start or an end time of the action, hence we can say that we require present continuous tense here. So, the correct option is C - 'Pulkit is working on a big project.' Option A is incorrect as it doesn't have an auxiliary to define the tense. Option B is incorrect, as it is neither present continuous, nor perfect continuous because even perfect continuous requires 'has'. Option D is incorrect, as it is neither present continuous nor perfect continuous, as even perfect continuous requires 'been'.