What does the R code z <- f[1:10, ] do?

What does the R code
z <- f[1:10, ]
do?

A.
Assigns the first 10 rows of f to the vector z

B.
Assigns the 1st 10 columns of the 1st row of f to z

C.
Assigns a sequence of values from 1 to 10 to z

D.
Assigns the 1st 10 columns to z