What new experimental method was used after the team of scientists had the hypothesis about mirror neurons?

mri “monkey see monkey do” tests on monkeys performing tasks

double blind placebo experiments

mri “monkey see monkey do” tests on humans performing tasks

placebo experiments

The mirror neurons were first discovered on monkeys, and they were tested with fMRI (functional Magnetic Resonance Imaging) - so the correct answer is "MRI “monkey see monkey do” tests on monkeys performing tasks". This means that an MRI scan was performed as the monkeys watched people perform tasks.