The correct spelling of the phrase "most picnic" is actually "mustn't pick a." The pronunciation of "mustn't" is /ˈmʌstənt/ and "pick" is /pɪk/, which are merged together to form "pic". "A" is pronounced as /ə/. Putting these sounds together gives "mustn't pick a," which phonetically makes more sense than "most picnic". Remembering the correct spelling can prevent confusion and ensure effective communication.