Multi-choice problem: Continue writing the next sentence in this paragraph:

How to use contractions
Understand when it is appropriate to use a contraction.
From a technical standpoint, contractions are not necessary in written english. The grammatically correct way to write requires the full version of every word.

[A]. In standard english, no whole word should be connected to a full-out contraction. If necessary, look online to see what forms are appropriate before switching to a full-written form..
[B]. Contracting, or shortening words, should only be done for stylistic purposes and for specific types of writing. If you are writing something where you are " talking " directly to your reader, you may use contractions..
[C]. If you simply want to reconstruct a verb, you have a red flag that it is appropriate to use a contraction. When using a contraction, do not use an isolated letter as this will likely confuse the recipient..
[D]. There are 5 most commonly used contractions in written english. These include spaces, adjectives and commas..
[B].