If the question here is "what does the word alternatives mean", then the answer is: (of one or more things) available as another possibility.
If the question is really "which word means alternatives", then "possibilities" would be my choice.
Given all that, I also agree with 5jj in his assessment that none truly work. They all feel awkward.
The note on usage from the Oxford Dictionary of the English Language Unabridged edition:
USAGE 1 Alternate can be a verb, noun, or adjective, while alternative can be a noun or adjective. In both American and British English, the adjective alternate means 'every other' ( : there will be a dance on alternate Saturdays) and the adjective alternative means 'available as another choice' ( : an alternative route;: alternative medicine; alternative energy sources). In American usage, however, alternate can also be used to mean 'available as another choice': : an alternate plan called for construction to begin immediately rather than waiting for spring. Likewise, a book club may offer an 'alternate selection' as an alternative to the main selection. USAGE 2 Some traditionalists maintain, from an etymological standpoint, that you can have only two alternatives (from the Latin alter ‘other (of two); the other’) and that uses of more than two alternatives are erroneous. Such uses are, however, normal in modern standard English.
