In the following sentence, some parts may contain an error. Read carefully and choose which numbered segment is incorrect, or choose "No error" if the sentence is correct: "On Sundays (1) I prefer reading (2) than going out visiting my friends. (3) No Error (4)".

Introduction / Context:
This question tests correct usage of the verb "prefer" followed by two contrasted activities. The sentence is divided into numbered parts: "On Sundays (1) I prefer reading (2) than going out visiting my friends. (3) No Error (4)". The candidate must choose which numbered segment contains the error. The key issue is the preposition that follows "prefer" when two alternatives are presented.

Given Data / Assumptions:

• Part (1): "On Sundays"
• Part (2): "I prefer reading"
• Part (3): "than going out visiting my friends."
• Part (4): "No Error"
• We assume standard exam rules for the verb "prefer".

Concept / Approach:
The usual pattern with "prefer" is "prefer A to B". Therefore, when contrasting two actions, we should say "I prefer reading to going out visiting my friends." Using "than" after "prefer" is considered incorrect in formal grammar. The time phrase "On Sundays" and the clause "I prefer reading" are both acceptable. The error is in segment (3), where "than" is used instead of "to".

Step-by-Step Solution:
Step 1: Read the full sentence: "On Sundays I prefer reading than going out visiting my friends." Step 2: Recognise the structure of preference: "prefer reading ... going out visiting my friends." Step 3: Recall the standard pattern "prefer A to B". Step 4: Notice that segment (3) uses "than going out visiting my friends" rather than "to going out visiting my friends". Step 5: Check segments (1) and (2) and see that they are grammatically sound. Step 6: Conclude that the incorrect part is segment (3), so the answer should be option "3".

Verification / Alternative check:
Rewrite the corrected sentence: "On Sundays I prefer reading to going out visiting my friends." This version follows the usual pattern and sounds natural. Compare with other examples like "I prefer tea to coffee" and "They prefer staying at home to going to crowded places." These sentences confirm that the preposition "to" is consistently used after "prefer" when two choices are contrasted. Therefore, using "than" in segment (3) is clearly incorrect.

Why Other Options Are Wrong:
Option (1) "On Sundays" is a correct adverbial phrase of time. Option (2) "I prefer reading" correctly uses "prefer" followed by a gerund, which is common and acceptable. Option (4) "No Error" cannot be correct because we have identified a definite error in segment (3).

Common Pitfalls:
Learners often mix up the structures "prefer A to B" and "like A better than B". Because "better than" uses "than", they mistakenly apply "than" to "prefer". Remembering that "prefer" naturally pairs with "to" and "better" often pairs with "than" helps avoid this confusion. Practising several sentence pairs with these two patterns can fix the structure in memory.

Final Answer:
The error is in segment (3), where "than going out visiting my friends" should be "to going out visiting my friends". Therefore, the correct answer is "3".