Which sentence does not contain a hidden verb? the lab assistant gave a demonstration on how to create a suitable sample. the office manager analyzed the financial reports. the associate dean arrived at the conclusion that the computer labs are outdated. the information technology department has a requirement for technical training. do you have a need for a new laser printer?

the office manager analyzed the financial reports.

A hidden verb is a verb turned into a noun. I've put the hidden verbs in parenthesis below. I given the revision for eliminating them to make the sentence clearer. 
the lab assistant gave a (demonstration) on how to create a suitable sample. [The lab assistant demonstrated how to create a suitable sample]
the associate dean arrived at the (conclusion) that the computer labs are outdated.
[The associate dean concluded that the computer labs are outdated.]
the information technology department has a (requirement) for technical training.
[The information technology department requires technical training.]
do you have a (need) for a new laser printer?
[Do you need a new laser printer?]

They were cautious and aggressive because they had a theory that they would revolt at any time