Answer:
A
Step-by-step explanation:
In Chinese, the first three counting numbers (1, 2, and 3) are the most similar because they are essentially just that number of lines (see the attachment).
As you can see, "1" is just one horizontal line, "2" is two horizontal lines, and "3" is three horizontal lines. From 4 and up, however, they're all very different.
Hope this helps!