Multi checkbox search in rails

Now working on single checkbox search, I need multi checkbox search, my code is below:

<form action="<%= search_path %>" method="get">
  <%= check_box_tag :title, "A" %> A
  <%= check_box_tag :title, "B" %> B
  <%= check_box_tag :title, "C" %> C
</form>

Like this

For example titleA, B, C & D I need search all checkbox checked