Tom sends an Elgamal ciphertext, encrypted under Anna's public key, to Anna.

The public key is (p, q, g, h), and the ciphertext is (c₁, c₂) where c₁ g^r mod p, c₂ m h^r mod p

An adversary intercepts the ciphertext, and does the following:

He chooses s, t and computes:

1. d₁ g^s mod p, d₂ t h^s mod p
2. c₁' c₁ d₁ mod p, c₂' c₂ d₂ mod p

Then he sends (c₁' , c₂') to Anna.

What would be the decryption result obtained by Anna?

1: r t mod p

2: t m mod p

3: r s mod p

4: s m mod p