Business & farm

Usually your investment is at risk and is not limited to your initial investment, but includes all earnings or losses as well.  The only way your investment is not at risk is if you have used any of the following to fund the investment:

• Non-recourse loans used to finance the business
• Cash, property or borrowed amounts used in the business that are protected against loss by a guarantee, stop-loss agreement, or other similar arrangement (excluding casualty insurance and insurance against tort liability)
• Amounts borrowed for use in the business from a person who has an interest in the business, other than as a creditor.

Since you state you used your own funds for the investment, then you should mark "All of my investment in this activity is at risk".

Passive activity is a different situation and doesn't rely on risk.  If you do not actively participate in the business the income or loss is passive to you.  The IRS defines activities that are not passive as:

• Trade or business activities in which you materially participated for the tax year.
• A working interest in an oil or gas well that you hold directly or through an entity that doesn’t limit your liability (such as a general partner interest in a partnership). It doesn’t matter whether you materially participated in the activity for the tax year. However, if your liability was limited for part of the year (for example, you converted your general partner interest to a limited partner interest during the year) and you had a net loss from the well for the year, some of your income and deductions from the working interest may be treated as passive activity gross income and passive activity deductions. See Temporary Regulations section 1.469-1T(e)(4)(ii).
• The rental of a dwelling unit that you also used for personal purposes during the year for more than the greater of 14 days or 10% of the number of days during the year that the home was rented at a fair rental.
• An activity of trading personal property for the account of those who own interests in the activity. See Temporary Regulations section 1.469-1T(e)(6).
• Rental real estate activities in which you materially participated as a real estate professional. See Real Estate Professional, later.