In English grammar, identify the part of the sentence that contains an error in subject verb agreement in the sentence All the furnitures has been replaced by the landlord.

Introduction / Context:
This question belongs to the category of error spotting in English grammar, specifically subject verb agreement and use of countable or uncountable nouns. The sentence given is All the furnitures has been replaced by the landlord. Learners are expected to identify which part contains the grammatical error. Such questions are very common in competitive examinations because they quickly test whether candidates know correct standard usage for everyday words and basic agreement rules in English sentences.

Given Data / Assumptions:

The complete sentence is All the furnitures has been replaced by the landlord.
The sentence is divided into four parts: All the furnitures, has been replaced, by the landlord, and No error.
Only one part contains the mistake according to standard English usage.
The noun furniture is normally treated as an uncountable noun in modern standard English.
The context suggests that the landlord has changed all the tables, chairs, cupboards and other items in the house or flat.

Concept / Approach:
The key concept is the distinction between countable and uncountable nouns and how they behave in singular and plural constructions. The noun furniture is an uncountable noun similar to luggage, information, and advice. Such nouns do not generally add a plural s in standard usage. We say much furniture or pieces of furniture, not furnitures. The verb phrase has been replaced is a present perfect passive form used with a singular or uncountable subject, so it is grammatically fine. The prepositional phrase by the landlord is also correct, since it simply identifies the agent responsible for the replacement.

Step-by-Step Solution:
Step 1: Read the full sentence and understand the general meaning, which is that the landlord replaced all the furniture. Step 2: Examine part A All the furnitures and check whether the noun form is correct for this meaning. Step 3: Recall that furniture is an uncountable noun and that standard English does not use a plural furnitures. Step 4: Check parts B and C, that is has been replaced and by the landlord, and see that both are grammatically acceptable. Step 5: Conclude that the error lies in part A, and the correct sentence should read All the furniture has been replaced by the landlord.

Verification / Alternative check:
To verify, rephrase the sentence using a clearly singular quantity. For example, you can say All this furniture has been replaced. The verb has still agrees with the uncountable singular idea of furniture. If we needed to show separate items, we would say All the pieces of furniture have been replaced and then the subject becomes plural pieces, not furniture itself. No other correction is needed in the sentence, as has been replaced is the right passive structure for a completed action and by the landlord is the correct prepositional phrase describing who carried out the action.

Why Other Options Are Wrong:
Option B has been replaced is a standard present perfect passive construction that correctly matches the uncountable subject furniture, so it has no error. Option C by the landlord correctly uses a by phrase to introduce the agent in a passive sentence and therefore remains grammatically sound. Option D No error cannot be correct because we have already identified a clear nonstandard plural form furnitures in part A.

Common Pitfalls:
Many learners wrongly assume that adding s to any noun will make its plural. For uncountable nouns like furniture, advice, information, scenery, and baggage this rule does not work. Another common error is to change the verb to have in an attempt to match a mistaken plural furnitures, which makes the sentence doubly incorrect. A safer approach is to memorize some of the most frequent uncountable nouns and practice using expressions like some furniture, much furniture, or several pieces of furniture instead of incorrect plural forms.

Final Answer:
All the furnitures