The given sentence gives a clue to the correct answer by using the noun phrase 'in favour of the manager'. This indicates that the new manager has given positive output. Thus, we can rule out option D 'declined' as it means decreased.
Of the other given options "arisen" means occurred as a result of. Using this would imply that profitability started due to the new manager. This is nor indicated in the sentence. However, the sentence indicates growth but does not mention it. We need a verb which indicates increased productivity.
"Increased" means become greater in size or amount. This suits the context as it matches the context.
"Developed" means becoming more mature, advanced or elaborate. This is not used in reference to productivity which is easily quantifiable.
Thus, option B is correct.