
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
Given circle $C$: $x^{2}+y^{2}-4x-5=0$.
(I) Determine the positional relationship between circle $C$ and circle $D$: $(x-5)^{2}+(y-4)^{2}=4$, and explain the reasoning;
(II) If line $l$ passes through point $(5,4)$ and is tangent to circle $C$, find the equation of line $l$.

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