How does the read$\_$csv function determine column types when reading in a dataset?

Hint: Check the help file for the read$\_$csv function and look at the description of the col$\_$types argument.

Question $1$Select one or more:

a$.$

it sets all variables to either numeric or character

b$.$

it assigns them by matching randomly chosen rows of the dataset

c$.$

it uses a vector of col$\_$types if it is provided by the user

d$.$

it imputes column types from the first $1000$ rows of the dataset