(Please explain in detail and don't forget questions 3 and 4. Thank you!)

The GL limited partners was organized at the beginning of the current year. G, the general partner, contributed $10 for a 10 percent interest in profits, losses and capital, and L, as limited partner, received a 90 percent interest in profits, losses and capital in exchange for a capital contribution of $90. The partnership immediately purchased a rental apartment building for $1,000, paying $100 in cash and issuing a $900 purchase money note, with interest payable currently and a lump-sum principal payment due in 20 years. Determine each partners initial outside basis under each of the following alternatives:

1. The note is recourse, and hence the partnership (and G as its general partner) is personally liable on the note. As a limited partner, L is required to make no additional capital contributions beyond the $90 he contributed upon formation. L has no personal liability with respect to the note.
2. Same as (a), except that under the partnership agreement L, as the limited partner is obligated to contribute additional capital of $900 to the partnership in the future (making the total required capital from L $990).
3. Same as (a), except that L has assumed and promised to pay the entire note as it becomes due. Assume that the holder of the mortgage could proceed directly against L as well as G and the partnership if the note is not paid. Also assume that if the holder of the mortgage sued G or the partnership for payment, G and the partnership would sue L for the same amount since Ls assumption made him ultimately liable on the debt.
4. Same as (a), except that L has guaranteed the note in a side agreement directly with the holder of the mortgage.