All of the students at Risedale High School were sent home early on Tuesday 1 April 2003 due to a bomb scare in the science block. The police were called in after a brown parcel had been left unaccounted for in the physics laboratory. Bomb experts later revealed that it was a hoax. However, the police say that they are treating the matter seriously. So far it is known that: John Dawes, an ex-pupil, was seen in the school grounds on Tuesday 1 April. In the previous week, a group of sixth-form science students had been making minor explosives in the chemistry laboratory. The headteacher had recently made cuts in the science budget. The science staff opposed the recent cuts and had threatened to respond with unreasonable behaviour. Joyce Denver (physics teacher) had bought a birthday present for her son before school on Tuesday 1 April. A recent Inspection Report noted that the school has a high truancy rate. Five pupils have been expelled since the start of the academic year.

Question: The science staff were free from suspicion.
Options:
A. true, B. false, C. uncertain
Answer: "B"