The correct answer is A. A collision attack targets a hash function by attempting to find two different inputs that produce the same hash output. In CEH cryptography topics, hashing is a one-way mathematical function used mainly to verify integrity, not to encrypt data. A good hash should produce a unique fixed-length digest for each different input, and even a tiny change in the original data should create a very different hash value. CEH material states that, in hash algorithms, a collision occurs when two or more distinct inputs produce the same output. It also explains that collision attacks are attacks against hashing algorithms where two or more files create the same output, which should not normally happen. Option B is incorrect because public keys relate to asymmetric cryptography, not hash collisions. Options C and D are incorrect because collision attacks do not split hashes to recover plaintext or private keys.