A score of three is best because the essay is clearly focused on the task, and it contains no errors in spelling and grammar.

A score of one is best because the writing does not stay on task, and it contains many spelling and grammar errors.

A score of two is best because, although the writing stays on task, there are some errors in spelling and grammar

C. A score of two is best because, although the writing stays on task, there are some errors in spelling and grammar

Explanation:

So, two basic criteria for giving the score to this essay are focus on the task and spelling and grammar errors.

This is supposed to be a persuasive essay; it needs to convince the mayor in the need for a park. The author states the current situation, emphasizes the dangers of playing in the street, provides some expert evidence which suggest benefits of having a park and proposes a possible solution for the situation. Considering this, it's fair to say that the author stayed foccused to the task.

However, there are some errors found throughout the passage (they need to does instead of they need to do, he closest instead of the closest, les instead of less etc.)

With this in mind, it would be the most adequate to give this essay a score of two.