Ruby syntax scoping question

### How is method(:bar) scoped in this case? (Within class A? Within class B? neither? Is the new B instance implicitly "self" within the do block?)
### The '@' in @var makes var an instance variable?
### A.new.foo returns a hash containing the key :key?

class A
  def foo
    @val = B.new do
      {
        key: method(:bar)
      }
    end
 end
end