Which of the following extracts first element from the following R vector?

> x <- c("a", "b", "c", "c", "d", "a")

A. List B. Matrix C. Data Frame D. Vector

A. A list of elements B. A one-dimensional array C. A two-dimensional array D. A data frame

A. my_list <- c(1, "hello", TRUE) B. my_list = list(1, "hello", TRUE) C. my_list(1, "hello", TRUE) D. list(my_list = c(1, "hello", TRUE))

A. List B. Matrix C. Data Frame D. Array