Step 1: Understand the time complexities.
- **Bubble sort (worst case)** (A): The worst-case time complexity of bubble sort is **$O(n^2)$**.
- **Deleting head node in singly linked list** (B): Deleting the head node takes **$O(1)$** time.
- **Binary search** (C): Binary search has a time complexity of **$O(\log n)$**.
- **Worst case of merge sort** (D): Merge sort has a worst-case time complexity of **$O(n \log n)$**.
Step 2: Arrange in increasing order.
From lowest to highest, the correct order is:
- **(C)** Binary search: $O(\log n)$
- **(B)** Deleting head node: $O(1)$
- **(D)** Merge sort: $O(n \log n)$
- **(A)** Bubble sort (worst case): $O(n^2)$
Step 3: Conclusion.
Thus, the correct order is **(C), (B), (D), (A)**.