The requirement is to update 500 Leads using Data Loader, ensuring that blank (null) values in the CSV file (for Email or Phone) do not overwrite existing values in Salesforce records. The Salesforce Data Loader provides a specific setting to control this behavior, making A the correct answer.
Here’s why A. Open Data Loader -- > Setting -- > Uncheck the " Insert Null Values " checkbox is the correct answer:
Data Loader Behavior: By default, when you update records via Data Loader, blank values in the CSV file are treated as nulls and will overwrite the corresponding fields in Salesforce with null, replacing any existing data. For example, if a Lead record has Phone = " 555-1234 " and the CSV has a blank Phone column for that ID, the update will set Phone = null unless configured otherwise.
Insert Null Values Setting: The " Insert Null Values " checkbox in Data Loader’s Settings (found under Settings > Settings) determines whether blank CSV values are treated as nulls.
Checked: Blank values in the CSV overwrite existing field values with null (default behavior).
Unchecked: Blank values in the CSV are ignored, and the existing field values in Salesforce are preserved.
Meeting the Requirement: Unchecking " Insert Null Values " ensures that if a row in the CSV has a blank Email or Phone, those fields in the corresponding Lead record remain unchanged (e.g., retaining Email = " john@example.com " instead of setting it to null). Only non-blank values in the CSV (e.g., a new Phone number) will update the records.
Process: Open Data Loader, go to Settings > Settings, uncheck " Insert Null Values, " then proceed with the Update operation using the CSV file with ID, Email, and Phone columns.
Now, let’s examine why the other options are incorrect:
B. Null values cannot be ignored. If they are present in CSV, they get updated as null: This is false. Data Loader provides the " Insert Null Values " setting specifically to ignore nulls when unchecked, contradicting this option.
C. Open Data Loader -- > Setting -- > Check the " Ignore Null Values " checkbox: There’s no " Ignore Null Values " checkbox in Data Loader Settings. The relevant option is " Insert Null Values, " which must be unchecked (not checked) to ignore nulls, making this option incorrect due to inaccurate terminology and logic.
D. Modify the CSV file and remove the records which have null values, and update them manually: This is a workaround, not a best practice. Manually editing 500 records is inefficient and error-prone when Data Loader’s built-in setting can handle this automatically.
E. Null values do not get updated through Data Loader: This is false. By default, null values do update fields unless the " Insert Null Values " setting is unchecked.
[References:, , Salesforce Data Loader Guide: Settings – Details the "Insert Null Values" option and its impact on updates., Salesforce Help: Updating Records with Data Loader – Explains handling null values in CSV imports/updates., , , , , ]
New Zealand 
French Guiana 
Guadeloupe 
Thailand 
France 