How to access List type from an option set in conditions of the Rules module?
These are the Rules Conditions you should use:


Entity has field "field_weight_options", which is the machine name of the field you want to check.
List contains item (for your field_weight_options, which is a list since it is a multi value field) and with the value (such as "2lb") you want to check for.


What is crucial in the context of this question, are these 2 Rules Conditions. Especially because of your "field_weight_options is a multiple value" (only "List contains item" is the Rules Condition that will do the trick ...).

PS: This answer applies to D7.