Sequence of Tenses in Indirect Speech

My mother said to me: "Plants grow in soil, so you should put the tree in the garden."

Select correct answer in indirect speech.

- [ ] My mother said to me that plants would grow in soil, so I should put the tree in the garden.
- [ ] My mother said to me that plants grow in soil, so I ought to put the tree in the garden.
- [x] My mother told me that plants grow in soil so I should put the tree in the garden.
- [ ] My mother told me that plants grew in soil, so I should put the tree in the garden.
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1. The fact that plants grow in soil is always true, so the tense remains the same.  
2. In the reported speech with the modal verb *should*, this word does not change.  
3. *Plants grow in soil* is a general truth, so the tense does not change in the indirect speech.  
4. The fact that plants grow in soil is always true, so the tense remains the same.
