At the beginning of the year, a firm has net fixed assets of $5,000 and accumulated depreciation of $1,500. At the end of the year, the firm has net fixed assets of $6,000. Which of the following statements MUST be true.

The firm sold fixed assets during the year.

The firm depreciated assets during the year.

There was no depreciation applied during the year.

The firm purchased fixed assets during the year.