Answer:
United States would be neutral.
Your answer is definitely the third one about Spain. The Spanish had nothing to do in the Pacific besides the Philippines.
Basically the United States aquired Guam and Puerto Rico from Spain and Cuba gained independence(under a heavy US sphere of influence, basically a puppet state). America also agreed to pay spain for these territories. It's important to note the US also annexed the Phillipines from Spain though America would lose control of the Islands and eventually grant the Phillipines independence in the mid 1900s
