Mintzberg's study in the 1960s came up with three important findings about a manager's routine. what are they, and are they probably still the same today?

Mintzberg findings about a manager's  routine published in the study in the 1960s are: 
-Managers rely on verbal communication more than written communication    because writing takes time
- Managers perform a variety of fragmented, brief task
- Managers work hard and for long hours- 60 hours/week
- Managers do not multitask, but stay focused on the important tasks at hand

Im pretty sure it’s is c