Tertiary butyl methyl ether on reaction with anhydrous HI gives an alcohol (A) and halide (B). Which of the following statements is correct ?
A. Alcohol (A) performs Lucas test immediately at room temperature
B. Halide (B) undergoes `S_(N^(1))` reaction most readily
C. Alcohol (A) on heating with copper gives formaldehyde
D. Halide (B) on heating with KCN mainly gives eliminated product .