The r code "test$\_$var $<-$ c$(1$:$5)"$ does the following:

Question $9$ options:

Assigns the values of $1$ and $5$ to the variable test$\_$var

Assigns a vector of $1,2,3,4,5$ to the variable test$\_$var

Assigns a matrix of size $1$:$5$ to the variable test$\_$var

Assigns a vector of $5,4,3,2,1$ to the variable test$\_$var