Q: if a program is invoked with "python program. py -r input. dat output. dat", what are the elements of argv?

there are four choices:

a. argv[0]: "-r input. dat output. dat"

b. argv[1]: "-r"
argv[2]: "input. dat"
argv[3]: "output. dat"

c. argv[0]: "program. py"
argv[1]: "-r"
argv[2]: "input. dat"
argv[3]: "output. dat"

d. argv[0]: "-r"
argv[1]: "input. dat"
argv[2]: "output. dat"