nil error on <% @people.each do |person| %>

Hi, I am trying to start off in my rails program with a select a person from a drop down list

as in “<% @people.each do |person| %> .”

 I get a "nil error" trying the drop down list, but in a regular list program I get the list of people.
I checked to model ad the controller and they look the same as the list,
 except I am trying to create a drop down list as opposed to a list/
Thanks for any help