
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Green Tree Publishing prices its popular children's book "Adventures in the Jungle" as follows:
\[ C(n) =\left\{\begin{matrix} 
15n, & \text{if } 1 \le n \le 30, \\ 
13n, & \text{if } 31 \le n \le 60, \\ 
12n, & \text{if } 61 \le n \le 90, \\
11n, & \text{if } 91 \le n.
\end{matrix}\right. \]
where \( n \) is the number of books ordered, and \( C(n) \) is the cost in dollars of \( n \) books. Determine for how many values of \( n \) is it cheaper to buy more than \( n \) books than to buy exactly \( n \) books.
A) 7
B) 8
C) 9
D) 10
E) 11

Present the answer in LaTex format: \boxed{Your answer}
user