The answer is b, 'clean.' It is the construction 'to have someone do something', which we can use when talking about making or causing someone (in this case Ali) do something (in this case, cleaning the blackboard,) It means the teacher makes Ali clean the blackboard everyday.

(b) clean "has" == To "have" somebody do something most commonly means to cause somebody to do something. (sub. "arranged for", "forced", "deputed the task to", "employed")