Indicate whether the specified cause is a necessary condition, a sufficient conditions, a necessary and sufficient condition, or neither a necessary nor sufficient condition for the following statement:
 "A single shot caused the first world war"
 tip: for a sufficient condition-- ask yourself, does this cause GUARENTEE the effect? For a necessary condition- ask yourself- is this effect happen without the cause, or is the cause necessary for the effect?
 A necessary condition
 A sufficient condition
 a necessary and sufficient condition
 netiher a necessary nor sufficient condition