
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
If $\sin{4x}\sin{5x}=\cos{4x}\cos{5x}$, then one value for $x$ is
A) $10^\circ$  
B) $20^\circ$  
C) $30^\circ$  
D) $45^\circ$  
E) $60^\circ$

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