30 free points have a good day

What aspects of lines have to be diffrent

Examine the following sets of events. set a: {1, 5, 7, 9, 14} set b: {2, 5, 6, 8, 14, 17} which of the following represents the intersection of set a and set b ? {∅} {5, 14} {1, 2, 5, 6, 7, 8, 9, 14, 17} {1, 2, 6, 7, 8, 9, 17}

What is the missing step in this proof ?