The correct passive form of the given sentence is:

☀ One’s valuables must be kept carefully.

Let's break down the options:

1. One’s valuables carefully are kept. (Incorrect) This option changes the word order and places "carefully" in an awkward position. In the passive voice, adverbs are typically placed after the verb "to be" or the main verb. The correct form should be "One’s valuables are carefully kept."

2. Ones valuables must kept. (Incorrect) This option is not in the passive voice. It still uses the active voice "must kept" instead of the passive "must be kept."

3. Ones valuables must be kept. (Incorrect) This option uses the passive voice "must be kept," but it omits the possessive "One’s" before "valuables," which is necessary to maintain the meaning of the original sentence.

4. One’s valuables must be kept carefully. (Correct) This sentence correctly uses the passive voice and conveys the same meaning as the original sentence. It includes the possessive "One’s" before "valuables" and retains the adverb "carefully" in the correct position after the verb "be kept."