New Construction? Is there any wall framing in the basement? If these are the only two pipes in the basement with no wall framing outlining a bathroom, it could be a floor drain which needs to be cut down, & a vent. Certainly there should be plans, or at least the builder or buyer should know if there should be a basement bath. I'm not sure about other regions, but I'm use to seeing a basement bath rough with at least 3 pipes. The closet/toilet, it's vent, and a stub-up for a lavatory. Full baths would have a square hole for the tub drain, (or another pipe for a shower) and it's respective vent.