In this error spotting question, identify the incorrect part in the sentence about trend analysts and what will be in or out.

Introduction / Context:
This error spotting question focuses on subject verb agreement and noun phrase structure in a sentence about trend analysts. The sentence reads Trend-analysts experts specializes in predicting what will be in and what will be out. While the general meaning is clear, one part contains a mismatch between a plural subject and a singular verb, and the noun phrase itself is awkward. Competitive exams frequently test such agreement errors because they are common in everyday writing.

Given Data / Assumptions:

• Part 1: Trend-analysts experts specializes
• Part 2: in predicting what will
• Part 3: be in and what will be out.
• Part 4: No error
• The intended subject is experts who specialise in trend analysis.

Concept / Approach:
The phrase trend analysts experts is intended to refer to experts in trend analysis. As written, it is somewhat redundant and should ideally be trend analyst experts or trend analysis experts. More importantly, experts is clearly plural, so the verb that follows must also be plural: specialise, not specializes. In standard English, the s form of the verb is used with singular third person subjects, whereas plural subjects take the base form without s. Because both the noun phrase and the verb form are problematic in part 1, this is the part that contains the error.

Step-by-Step Solution:
Step 1: Identify the main subject and verb in part 1: Trend-analysts experts specializes. Step 2: Recognise that experts is plural, so the verb should be specialise, not specializes. Step 3: Notice that the compound noun phrase trend-analysts experts is awkward and would more naturally be trend analyst experts or trend analysis experts. Step 4: Mentally correct the phrase to Trend analyst experts specialise in predicting. Step 5: Conclude that the error lies in part 1, due to both verb agreement and awkward noun structure.

Verification / Alternative check:
Rewrite the sentence in a corrected form: Trend analyst experts specialise in predicting what will be in and what will be out. This version uses a clear plural subject and matches it with the plural verb specialise. Parts 2 and 3, in predicting what will be in and what will be out, are grammatically sound and effectively express the idea of forecasting trends. Since the necessary corrections are concentrated in part 1, we can confidently mark part 1 as the segment containing the error.

Why Other Options Are Wrong:
Part 2 correctly introduces the prepositional phrase in predicting what will, which leads naturally into the subordinate clauses in part 3.

Part 3, be in and what will be out, uses parallel structure with will be in and will be out, and there are no grammatical mistakes.

Part 4, No error, is not correct because we have identified clear subject verb agreement and noun phrase issues in part 1.

Common Pitfalls:
Students sometimes focus only on the verb form and forget to check whether the noun phrase itself is well formed. When you see a hyphenated or compound term like trend analysts experts, it is worth checking whether it should be analysis experts or analyst experts instead. At the same time, always ensure that the verb agrees in number with the final noun in the subject phrase. Plural nouns like experts require verbs without the s ending in the present tense.

Final Answer:
The error is in part 1; the phrase should be Trend analyst experts specialise, not Trend-analysts experts specializes.