Hi Dhairya, that is actually a good question. From my point of view, these is how I would do in case of a low or high severity.
1) Hazards that fall into a low severity risk, are considered generally
acceptable and will not require further analysis. Additional mitigation can be done but is optional for hazards that fall into low severity risks..
2) Now, hazards that fall in between, more like a medium severity risk, are considered conditionally acceptable but these risks will require analysis and mitigation. These risks are conditionally acceptable because it can be considered as acceptable only when adequate mitigation are identified.
3) Hazards that fall into a high severity risk, are generally unacceptable. If
hazards at these level cannot be further mitigated to the point of
falling into an acceptance zone(low or medium), a formal risk/ benefit analysis
shall be performed and documented.
-Out of all the four, I believe that the least effective, the one that will not lower the risk of the device will be risk acceptance. Risk acceptance does not reduce any effects however it is still considered a strategy. This strategy is a common option when the cost of other risk management options such as avoidance or limitation may outweigh the cost of the risk itself.