The correct answer is: Only conclusion I follows.
The manager humiliating Sachin in the presence of his colleagues does not necessarily mean that Sachin was not popular with his colleagues. It is possible that the manager humiliated Sachin because he did not like him, or because he wanted to make an example of him. It is also possible that Sachin was popular with his colleagues, but that the manager did not care about that.
Conclusion I is a valid deduction from the statement. If the manager humiliated Sachin in the presence of his colleagues, then it is likely that the manager did not like Sachin.
Conclusion II is not a valid deduction from the statement. The manager humiliating Sachin in the presence of his colleagues does not necessarily mean that Sachin was not popular with his colleagues.