When using LINQ with custom objects, what happens if you try to create a dictionary with duplicate keys using ToDictionary?

hard🧠 Conceptual Q10 of Q15

C Sharp (C#) - LINQ Fundamentals

When using LINQ with custom objects, what happens if you try to create a dictionary with duplicate keys using ToDictionary?

AThe compiler shows an error and code won't compile

BThe dictionary silently overwrites previous entries

CThe duplicate keys are ignored and only unique keys are added

DAn exception is thrown at runtime

Step-by-Step Solution

Solution:

Step 1: Understand ToDictionary behavior
ToDictionary requires unique keys; duplicates cause errors.
Step 2: Runtime behavior on duplicates
If duplicate keys exist, ArgumentException is thrown at runtime.
Final Answer:
An exception is thrown at runtime -> Option D
Quick Check:
Duplicate keys cause runtime exception in ToDictionary [OK]

Quick Trick: Ensure keys are unique before using ToDictionary [OK]

Common Mistakes:

MISTAKES

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