Answer: The correct form is "disposable".
Explanation: Although the word "dispose" ends in an "e", the "e" is dropped when the suffix "-able" is added to the root word because the suffix starts with a vowel sound ("a"). Moreover, the "e" is dropped because there is no "c" or "g" in the root. In that way, spelling the word formed with the root "dispose" plus the suffix "-able" as "disposeable" is incorrect: "disposable" is the correct form.
