At the time of herd improvement by $MOET$,generally $A$ ovum is released from each $B$ at the time of $C$. But by $D$ injection,$E$ ova can be produced from the ovary. After artificial insemination,$F$ embryos are collected at a time. Then each embryo is transplanted into a $G$. $A$ to $G$ in the above paragraph refers:

• A
  $A-$one,$B-$testis,$C-$spermatogenesis,$D-$hormone,$E-$more,$F-$one,$G-$mother
• B
  $A-$one,$B-$ovary,$C-$ovulation,$D-$hormone,$E-$more,$F-4$ to $10$,$G-$surrogate mother
• C
  $A-$one,$B-$ovary,$C-$ovulation,$D-$enzyme,$E-$more,$F-4$ to $10$,$G-$mother
• D
  $A-$one,$B-$ovary,$C-$ovulation,$D-$chemical,$E-$more,$F-$one,$G-$mother