At the very least, all these hypotheses appear capable of explaining the observed magnitude of coronal heating. Yet the detailed observations needed to distinguish among them have not been made. In addition, there are other unrelated theories of heating (the decay of neutrons leaking out from the sun, dissipation of heretofore unobserved massive subatomic particles, and so forth) that cannot be ruled out with existing observations or theoretical understanding. More than half a century after the corona was determined indisputably to be very hot, there is no consensus as to which particular mechanism or mechanisms actually does or do the heating.
Indeed, given current remote sensing techniques, a conclusive resolution of all these hypotheses may not even be possible. The surest course would be to sample directly the actual plasma in the solar atmosphere to as low an elevation as practical. This would entail careful measurement of the distributions of electrons and ions in terms of both direction and speed across a range of heights in the corona. The various mechanisms described above are thought to leave telltale signatures that would be evident in such measurements. A spacecraft mission to accomplish precisely this goal has been in the works for several decades now, but the technological difficulties involved are both daunting and costly to overcome. No matter what the mission concept, the spacecraft and its instrumentation would be subjected to enormous amounts of heat during the approach to the sun, so the pass through the solar atmosphere would have to be done quickly. Not only would spacecraft survival be a difficult proposition, but even the capture of meaningful data (and its transmission to Earth) would be a major challenge. You can read more about what a prospective solar probe mission could look like via the link provided below.
Hopefully, some time in the near future, funding will become available to support such a mission to finally resolve the mystery of coronal heating.