Final answer:
Postvocalic devoicing is a phonological process that causes voiced consonants to become voiceless after a vowel. The correct example of this process from the options is transforming 'cab' into 'cap', where the voiced 'b' becomes voiceless 'p'.
Step-by-step explanation:
The concept of postvocalic devoicing refers to a phonological process where voiced consonants become voiceless when they occur after a vowel. Among the given examples, the correct illustration of postvocalic devoicing is c) Transforming "cab" into "cap". This is because the voiced consonant /b/ is devoiced to the voiceless /p/ after the vowel sound in the word "cab." The other examples involve adding a plural 's' but do not depict the devoicing of a consonant following a vowel.
Some relevant patterns to recognize include the VCle pattern, where a long vowel is followed by a consonant and the 'le' ending, as in 'gable', and the VCCle pattern with a short vowel, as in 'rifle'. Following a vowel, consonant sounds can change based on specific phonetic rules in English. Understanding postvocalic devoicing alongside these patterns can enhance one's grasp of English pronunciation and spelling behaviors.