Final answer:
The measure of angle MNO cannot be determined without additional information or a diagram.
Step-by-step explanation:
The question does not provide sufficient context or information to accurately determine the measure of angle MNO. Without additional details or a diagram, it is impossible to ascertain whether angle MNO is 12°, 60°, 115°, or none of these options. Since we cannot make assumptions in mathematics without the proper information, I cannot provide a definitive answer to find the measure of angle MNO. For accurate assistance, it's necessary to have the complete problem statement or a diagram of angle MNO.