Answer :

Sure, let's work through this question step by step.

The question asks us to determine what percentage of all businesses in the United States are small businesses. The options provided are:

- 0%
- 19%
- 40%
- 60%
- 99%

We need to identify the correct percentage from these options.

We know that small businesses constitute a significant majority of all businesses in the United States. Given the options, the most reasonable percentage is quite clear.

Based on our knowledge:
- Small businesses indeed account for a very high percentage of the total businesses in the United States.
- The percentage is certainly much higher than 19%, 40%, or 60%.

Thus, the percentage of small businesses among all businesses in the United States is 99%.

Therefore, the correct answer is:
- 99%