In the sentence "The substitution of cream instead of milk in the recipe makes for a rich dessert.", one part contains a grammatical error. Identify the incorrect part.

Introduction / Context:
This error spotting question focuses on correct prepositional patterns with the noun "substitution." In English, certain nouns and verbs pair with specific prepositions, and mixing patterns can create redundancy or ungrammatical phrases. Here, the sentence uses both "substitution of" and "instead of," which sounds awkward and incorrect together.

Given Data / Assumptions:

• Sentence: The substitution of cream instead of milk in the recipe makes for a rich dessert.
• Parts:
  • Part A: "The substitution of cream"
  • Part B: "instead of milk in the recipe"
  • Part C: "makes for a rich dessert."
  • Part D: "No error"
• We must identify the part that contains the grammatical problem.

Concept / Approach:
With the noun "substitution" and the verb "substitute," the correct pattern is "substitution of X for Y" or "substitute X for Y." We do not normally say "substitution of X instead of Y," because "instead of" and "substitution" already express the idea of replacement, causing redundancy and incorrect preposition usage. Therefore, the phrase should be "The substitution of cream for milk in the recipe," not "instead of milk."

Step-by-Step Solution:

Step 1: Focus on the phrase "The substitution of cream instead of milk." This is the most likely area for a pattern error. Step 2: Recall the correct structure: "substitution of cream for milk," where "for" introduces the thing being replaced. Step 3: Recognise that "instead of" already carries the meaning of replacement and is redundant when used with "substitution of." Step 4: Conclude that Part B, "instead of milk in the recipe," is the incorrect segment; it should read "for milk in the recipe."

Verification / Alternative check:
Rewrite the sentence with the corrected phrase: "The substitution of cream for milk in the recipe makes for a rich dessert." This version sounds smooth, natural, and follows the standard collocation. There are no other structural or agreement problems. Both the subject and verb match, and the rest of the sentence is grammatically correct. Therefore, the only error lies in Part B.

Why Other Options Are Wrong:

Option A: "The substitution of cream" is correct and uses the right preposition "of" with the noun "substitution." Option C: "makes for a rich dessert." is a natural expression meaning "results in a rich dessert." Option D: "No error" is incorrect because we have clearly identified a pattern error in Part B. Option E: "The sentence is fully correct as written." is also wrong, since the structure "substitution of cream instead of milk" is not standard.

Common Pitfalls:
Students often overuse "instead of" when they want to express replacement, even when the word "substitution" already carries that meaning. This leads to incorrect combinations like "substitution of X instead of Y." A helpful memory rule is: use "substitute X for Y" or "substitution of X for Y," not both "substitution" and "instead of" in the same phrase. Recognising standard collocations is key to performing well in such questions.

Final Answer:
The incorrect part is "instead of milk in the recipe", which should be "for milk in the recipe."