Simple random and systemic random sampling

Differentiate between simple random and systemic random sampling

which of these examples best represents simple random sample

a) picking out the names of ever 10th person from a group of 200 people who drove a car

b) using a name generator to pick out 20 games of group of 100 students

C) selecting every 15th person in a group of 100 volunteers

d) selecting all the student in a group of 50 students