In the following sentence, identify the part that contains an error in standard English usage: “The goal of personal development is to learn and apply that (1) which enable us to attain emotional well being, understanding and (2) effectiveness, and to share this knowledge with others. (3)” If the sentence is correct, choose option 4 (No error).

Introduction / Context:
This is another error spotting question that checks subject verb agreement within a complex sentence containing a relative clause. The sentence describes the goal of personal development and the benefits it brings. The key grammatical issue lies in the verb form that follows the relative pronoun “which.” Recognising the true subject of the clause will help us choose the correct part containing the error.

Given Data / Assumptions:
The sentence is divided into three parts:
Part 1: “The goal of personal development is to learn and apply that”
Part 2: “which enable us to attain emotional well being, understanding and”
Part 3: “effectiveness, and to share this knowledge with others.”
Option 4 stands for “No error.”
We assume that “that which enable us” is intended to refer to some knowledge, skills, or principles that help us attain well being and effectiveness.

Concept / Approach:
The phrase “that which” in this sentence is treated as a singular idea. It can be understood as “that which enables us” or “what enables us.” When the antecedent is singular, the verb that follows should also be singular to maintain subject verb agreement. However, in the sentence, the verb used is “enable,” which is plural. This mismatch creates a grammatical error. The rest of the sentence about emotional well being, understanding, effectiveness, and sharing knowledge is structurally sound.

Step-by-Step Solution:
Step 1: Identify the relative clause: “which enable us to attain emotional well being, understanding and effectiveness.” Step 2: Determine the subject of the verb “enable.” It refers back to “that” or “that which,” which expresses a singular idea. Step 3: Apply the rule of subject verb agreement: a singular subject needs a singular verb, so we require “enables,” not “enable.” Step 4: Locate the part that contains this incorrect verb form. The word “enable” appears in Part 2. Step 5: Conclude that Part 2 is the part of the sentence with the grammatical error.

Verification / Alternative check:
We can rephrase the sentence in a simpler form to check agreement: “The goal is to learn and apply what enables us to attain emotional well being.” Here, it is clear that “what” or “that which” is singular, so “enables” is appropriate. If we tried “what enable us,” the sentence would sound wrong to native speakers and to trained readers. This reinforces that the verb must be singular. Therefore, the incorrect plural verb “enable” in Part 2 confirms that this is where the error lies.

Why Other Options Are Wrong:
Part 1 correctly introduces the subject and the infinitive phrase “to learn and apply that,” which is fine in context.
Part 3 correctly continues the objects “emotional well being, understanding and effectiveness,” and adds the coordinated infinitive “to share this knowledge with others.” There is no structural error here.
Part 4, “No error,” cannot be correct since we have already identified a clear subject verb disagreement in Part 2.

Common Pitfalls:
Many candidates see several nouns close to the verb and mistakenly match the verb to the nearest plural noun rather than to the true subject. In “that which enable us,” the verb is sometimes wrongly matched with “us,” which is plural, even though “us” is only an object. Always identify the grammatical subject of the clause before deciding on the verb form. Another pitfall is assuming “which” is always plural, which is not true; it follows the number of its antecedent.

Final Answer:
The error occurs in Part 2, because the verb should be “enables,” not “enable,” to agree with the singular idea “that which.”