https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/valueOf
"JavaScript calls the valueOf method to convert an object to a primitive value. You rarely need to invoke the valueOf method yourself; JavaScript automatically invokes it when encountering an object where a primitive value is expected."
Therefore:
5. Put the randomized variable into the xpath
evalXPath("/html/body/blockquote/form/center/table/tbody/tr["+options+"]/td[1]/input