Which best describes our standard English orthography?

A. There is a one-to-one relationship between sounds and letters: one sound is mapped to one letter.
B. There are too many exceptions and irregularities in our English spelling and decoding system to try to teach it explicitly to our students.
C. Syllables are the smallest units of spoken language that our alphabetic writing system represents.
D. The layers of our English language can be taught in an integrated way through a logical scope and sequence of instruction that introduces basic, high-frequency concepts first and builds on that with concepts of increasing complexity.