jQuery: How to make a field required if two specific options are selected

Validating a form w/ jQuery. For simplicity, user selects from three options: "A_or_B", "C", or "D" from a drop down list. If A_or_B is chosen then the "Name" field is required. If C or D, then it isn't. This was done like so:

$("#form").validate({
rules: {
    Name: {required: "#Letter[value=A_or_B]"}
}
});

Now I am required to make "A_or_B" 开发者_JAVA百科into two seperate entries, where either choice still makes the "Name" field required. How would I change the validation line for the Name field now that A and B are seperate entries on the drop down list?

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Not sure if this will work but it might be worth a try.

$("#form").validate({
  rules: {
    Name: {required: "#Letter[value='A'], #Letter[value='B']"}
  }
});