Answer:
a. It is not preferable for business standards.
Explanation:
A "colloquial pronunciation" refers to an "informal" way of pronouncing words. Such type of pronunciation is used in daily conversations and should not be used in formal settings (such as business setting).
One example of colloquial pronunciation is stating "yeah," instead of "yes." Another example is by stating "wanna," instead of "want to."
So, this explains the answer.