Answer:
B) discussion forum
Step-by-step explanation:
As in the given instance the company is widely spread as the offices are present in entire country, it would not be accurate to use instant messages or texting.
Though the discussion forums representing each office separately can be used. Which will provide conclusive summary of all the employees as they will represent the opinions of each office, also employees of each office would firstly discuss and then represent in office.
This clearly validates the opinion of each employee, and can be accessed country wide for this agenda.