Identify the part (A–E) that contains a grammatical error in the sentence below. If there is no error, choose option E (No error). Sentence (split into parts): A) Whatever work B) that which you undertake C) put your best D) efforts in it.

Introduction:
This item examines relative clause construction and redundancy. The phrase "that which" duplicates relativizers and should be simplified to either "that" or "which".

Given Data / Assumptions:

• Head noun: "work".
• Relative clause currently reads "that which you undertake".
• Imperative main clause: "put your best efforts in it".

Concept / Approach:
Standard English avoids stacking "that" and "which" together when they serve the same function. The correct forms are "whatever work you undertake" or "work that you undertake". Therefore, part B is erroneous due to redundancy.

Step-by-Step Solution:
1) Identify the determiner: "Whatever work" is acceptable as a free relative determiner.2) Remove redundancy: use "you undertake" directly after "whatever work".3) Result: "Whatever work you undertake, put your best efforts in it."4) Optional style tweak: "Put your best efforts into it" (prefer "into" with effort).

Verification / Alternative check:
Another correct version: "For any work that you undertake, put your best efforts into it."

Why Other Options Are Wrong:
A: "Whatever work" is fine.C–D: Imperative phrasing is acceptable; preposition choice can vary ("in/into").

Common Pitfalls:
Overusing both "that" and "which" together because both feel formal; only one is needed.

Final Answer:
B (Delete "that which" → "whatever work you undertake")