Mutual Exclusion Condition, Circular Wait Condition, Hold and Wait Condition, and No-Preemptive Condition

We know that for deadlock to occur, the four conditions (mentioned above) must be present, and therefore, to prevent deadlock we only have to prevent 1 of these conditions from occurring. a. Examining each condition separately is it possible to prevent it from happening (i.e. is each condition preventable?) b. Can implementing a prevention method cause other problems to arise? (explain) c. Why dont we simply pick the easiest to condition to stop and then do it? d. What affect can implementing deadlock prevention have on our operating system overall?