LQG.
1) It is widely believed that any theory of quantum gravity would require extremely high energies to probe directly, higher by orders of magnitude than those that current experiments such as the Large Hadron Collider can reach.
2) String theory as it is currently understood has a huge number of equally possible solutions, called string vacua and these vacua might be sufficiently diverse to explain almost any phenomena we might observe at lower energies.
Nuff said.