Cruelty means deliberately causing pain to others. As it is an extremely negative thing, the only expression I could select as correct from the above list is Voice against cruelty.
When you are against something, you think it is wrong and you cannot support it. If you raise your voice against it, it means you speak out loudly against it to show your disapproval:
- You mustn’t be afraid to raise your voice against cruelty.
You can also raise your voice for something, but that means showing your support:
- Never be afraid to raise your voice for justice and equality.
If you raised your voice for cruelty, it would mean telling people that you think cruelty is a good thing.
The preposition towards means ‘in the direction of something’, for example:
- Lily ran towards her mother. (Lily ran in the direction of her mother.)
It makes no sense to say Voice towards cruelty.
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