Which of the following women told her husband to have sex with her slave girl: Sarah, Rachel, or Leah?

All of them

Sarai [Sarah] said unto Abram, Behold now, the LORD hath restrained me from bearing: I pray thee, go in unto my maid; it may be that I may obtain children by her. And Abram hearkened to the voice of Sarai. Genesis 16:2

When Rachel saw that she bare Jacob no children, Rachel envied her sister ... And she said, Behold my maid Bilhah, go in unto her ... And she gave him Bilhah her handmaid to wife: and Jacob went in unto her. Genesis 30:1-4

When Leah saw that she had left bearing, she took Zilpah her maid, and gave her Jacob to wife. And Zilpah Leah's maid bare Jacob a son. Genesis 30:9-10