Split: CSV upload with multiselect field not working right

I am having a problem with SELECT custom field. I want to have a dropdown box where you can make one selection out of several options. I want to have the following choices:

$ (<$10pp)
$$ (<$20pp)
$$$ (<$30pp)
$$$$ (<$40pp)
$$$$$ (>$40pp)

In the Option Values (of the Custom Field) box I entered:

$ (<$10pp),$$ (<$20pp),$$$ (<$30pp),$$$$ (<$40pp),$$$$$ (>$40pp)

But these values will not save and the custom field dropdown is empty. What am I doing wrong or am I using the wrong type of field?

Thanks
Stacey