Final answer:
The per transaction limit for SOSL in Salesforce is 2,000 records returned. This limit applies regardless of whether the search is conducted synchronously or asynchronously.
Step-by-step explanation:
The per transaction limit for SOSL (Salesforce Object Search Language) in Salesforce is 2,000 records returned. When using SOSL, you can search across multiple objects at the same time, but it's important to keep in mind that there is a limit to how many records you can retrieve in a single search. If your query returns more than 2,000 records, Salesforce will only provide you with the first 2,000.
This limit is in place regardless of whether the query is executed synchronously or asynchronously. Therefore, option 1 (50,000 records) and option 3 (300 queries when asynchronous) are incorrect. While Salesforce does have limits on the number of queries you can execute, the numbers provided in options 2 (150 queries) and 3 are not related to the number of records returned by SOSL searches.