Answer:
Option C, You have to be more formal.
Step-by-step explanation:
Spoken language is very different from the written form of any language. This is so because while writing a language special emphasis is given to write a statement that is technically and grammatically accurate and must be conveying the desired literal meaning. However, while speaking the over all focus is to convey the correct/desired literal meaning only and thus writing a language is challenging as compared to speaking.
Thus, option C is correct