The letter style in which all lines begin at the left margin is called "justified."
Here's why:
1. Justified text aligns with both the left and right margins.
2. This style creates a straight edge on both sides of the paragraph.
3. Each line starts at the left margin and ends at the right margin.
4. It gives a clean and organized look to the text.
So, in the context of your question, the correct answer is D. justified.
