Final answer:
The claim that all net capital gains are included in net investment income is incorrect as net investment income encompasses various income sources and exceptions may apply based on tax regulations.
Step-by-step explanation:
The statement that All net capital gains are included in the definition of net investment income is false. Net investment income can include various types of income such as interest, dividends, and rental income. While net capital gains are often a significant part of net investment income, there are situations where some types of gains may be excluded based on specific tax rules or investment vehicles.