
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
A real estate developer invested 810,000 yuan to build an office building. The renovation cost in the first year was 10,000 yuan, and it increased by 20,000 yuan every subsequent year. The office building is now rented out, generating an annual rental income of 300,000 yuan.
(1) After deducting the investment and various renovation costs, starting from which year will the developer begin to make a net profit?
(2) After several years, the developer wants to invest in other projects and has two options:
① Sell the building for 500,000 yuan when the average annual profit is maximized;
② Sell the building for 100,000 yuan when the total net profit is maximized;
Which option will result in more profit?

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