Sexual Reproduction Has Not Been Observed in Bd

Multiple Choice

Sexual reproduction has not been observed in Bd. A Bd sporangium initially contains a single, haploid cell. Which of the following processes must be involved in generating the multiple zoospores eventually produced by each sporangium?
1) S phase
2) cytokinesis
3) mitosis
4) meiosis

A) 1 and 2
B) 1 and 3
C) 2 and 3
D) 1, 2, and 3
E) 1, 2, and 4