The second maturation division of the mammalian ovum occurs:
1. Shortly after ovulation before the ovum makes entry into the Fallopian tube
2. Until after the ovum has been penetrated by a sperm
3. Until the nucleus of the sperm has fused with that of the ovum
4. in the Graafian follicle following the first maturation division
Until after the ovum has been penetrated by a sperm