Which statement is most appropriate?

Surveillance involves observing the activities of defined individuals without their knowledge.

Watching, looking and gathering evidence does not generally breach privacy standards and is a useful way of securing information in a fraud investigation:

a. It is sensitive and must be handled with care. One approach is to formulate a formal policy based on the premise that it should always be used at the start of an investigation. Some argue surveillance should only be carried out by experts. Simple undercover operations can yield results particularly where this is the only way of obtaining proof of a fraud.

b. It is sensitive and must be handled with care. One approach is to formulate a formal policy based on the premise that it should only be used when absolutely necessary. Some argue surveillance should only be carried out by experts. Simple undercover operations can yield results particularly where this is the only way of obtaining proof of a fraud.

c. It is sensitive and must be handled with care. One approach is to formulate a formal policy based on the premise that it should only be used when absolutely necessary. Some argue surveillance should only be carried out by auditors. Simple undercover operations can yield results particularly where this is the only way of obtaining proof of a fraud.

d. It is sensitive and must be handled with care. One approach is to formulate a formal policy based on the premise that it should only be used when absolutely necessary.

Some argue surveillance should only be carried out by experts. Complex undercover operations can yield results and is a frequently used way of obtaining proof of a fraud.