Explanation:

 Explain 

Checking C-D:

She always speaks to him was summoned for a hearing.

The sentence doesn't make any sense contextually. The pair A-E is hence invalid.

Checking A-E:

Entering into parallel pecuniary relationships with stakeholders can be detrimental to the interests of a company, given that such parties influence decision making.

The above sentence is correct both grammatically and contextually.

Checking B-F:

We thought he loved her but it turned out that he loved another girl.

The above sentence is also correct both grammatically and contextually.

Option C is hence the correct answer.