Answer:
Middle management
Step-by-step explanation:
Boris is currently overseeing the work of six pharmaceutical sales managers for a specific region so he is surely not in lower management. Also, overseeing a number of sales managers from a specific region makes him look like a regional manager. Also, Boris meets with four others in his company whose jobs are similar to his position. This means that Boris and the other four people also report to a senior manager or authority considering the organizational structure based on the given information. Hence, Boris is in middle management as senior managers have wide ranged responsibilities.