During meiosis, what happens to the chromosome number of a diploid cell by the end of meiosis II?

• A. It doubles, producing tetraploid cells (from $2n$ to $4n$).
• B. It is reduced by half, producing haploid cells (from $2n$ to $n$).
• C. It becomes an odd number of chromosomes due to crossing over changing chromosome count.
• D. It remains the same, producing diploid cells (from $2n$ to $2n$).

Answer: (B)