
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
Let \( f(x) = \sin x \), \( f_1(x) = f'(x) \), \( f_2(x) = f_1'(x) \), ..., \( f_{n+1}(x) = f_n'(x) \), with \( n \in \mathbb{N} \). Then \( f_{2005}(x) = \) （ ）
A) \( \sin \)
B) \( -\sin \)
C) \( \cos \)
D) \( -\cos \)

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