I would like all of our employees to know (144), starting next month, we' II be making some changes in the company. The other board members and I have decided that it' s high time we renovate our offices and (145) some of our equipment. Bentley is the architectural firm which we have chosen for this project.
The first phase is scheduled to begin on the first floor, working up to the fourth. The whole project should be completed by the end of the year. We are very enthusiastic about this modernization and we look forward to it being a very successful project. To make the work easier, everyone is invited to relocate to nearby (146) offices (see the attached).
We will do everything to make this move as comfortable as we can without disrupting your work or other activities. We appreciate your cooperation and understanding, looking forward to seeing you back here upon completion of the remodeling project.
(44)

A. what
B. whether
C. when
D. that