Suppose list is an ArrayList containing five String objects. Which statement removes the first element from the list and stores it in the variable str$?$

a$.$

str $=$ list.get$(0)$;

b$.$

str $=$ list.remove $(0)$;

c$.$

str $=$ list.set$(0,$ null$)$;

d$.$

str $=$ list.add$(0,$ null$)$;

e$.$

str $=$ list.remove$($list$.$size$()-1)$;