Final answer:
Option C (Do, said, was, of) contains irregular words, which have pronunciations that don't follow standard phonetic rules, making them distinct from phonetically predictable words.
Step-by-step explanation:
Words that cannot be sounded out according to regular pronunciation rules are called irregular words. The list that contains irregular words is C) Do, said, was, of. Each of these words has a pronunciation that does not conform to standard phonic rules. For example, 'said' is pronounced as /sɛd/ instead of /seɪd/, 'was' is /wəz/ instead of /wɔs/, and 'of' is pronounced as /əv/ instead of /of/. These anomalies in pronunciation make them irregular words, which can be challenging for learners of English to decipher without prior knowledge or exposure.