The correct answer is Double hashing.

Key Points

• Double hashing is an open addressing technique used in hash tables to resolve collisions.
• It is considered free from primary and secondary clustering problems, which makes it more efficient than linear or quadratic probing.
• In double hashing, two hash functions are used to calculate the probe sequence:
  • The first hash function determines the initial position.
  • The second hash function determines the step size for probing.
• Double hashing ensures a better distribution of keys and reduces the likelihood of clustering.

Additional Information

• Linear Probing (Option 1) – Suffers from primary clustering, where consecutive groups of occupied slots form, leading to longer search times.
• Quadratic Probing (Option 2) – Reduces primary clustering but can still suffer from secondary clustering (where different keys follow the same probing sequence).
• Double Hashing (Option 3) – Uses a second hash function to determine the probe interval, making it resistant to both primary and secondary clustering.
• Rehashing (Option 4) – This is not a probing technique but rather a resizing strategy when a hash table becomes too full.