The number of IT employees out of all employees working in an office of Google
Step-by-step explanation:
The answer is the first one, because the rest Just describes a group of People, a subset is a part of a larger group of related things, while the others describes just a group of people, the first one which is the answer describes a group of people that's part of a larger group of people,
The subset is the IT employees working in an office for Google
whIle the main set is All employees working in an office of Google
