In cases like this, it's always a good idea to look at the HTML you are producing. In this case you'll get something like:

<option value=Desktop Products>Desktop Products</option>
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And any browser will interpret that as:

<option value="Desktop" Products>Desktop Products</option>
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So what you really want is:

<option value="Desktop Products">Desktop Products</option>
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You can only omit quotes around HTML attribute values when they only contain alphanumeric characters. Your attribute contains a space, so it must be quoted. In fact it's a good habit to get into to always quote all HTML attribute values.