1.3 Subsetting a column of a dataframe

We want to print observations 21 and 30 only for the variable Min of the dataframe Pedometer.
Which code is not correct?

1. Pedometer[c(21,30),”Min”]
2. Pedometer$Min [c(21,30)]
3. Pedometer$Min [21:30]

(Multiple choice: just type the number of the correct answer)