Answer:
The correct option is D: Concealment investigation
Step-by-step explanation:
Marks suspects a concealment crime and hence would use concealment investigative method to tackle this. Concealment occurs when documents that might prove as evidence are being manipulated. This may include manipulating the sales invoices, checks, sales report, purchase invoices etc. It also involves the modification or outright deletion of records from the database of a company. Mark would have to use concealment-based investigation as he will have to look at his books with the aim of looking for any manipulated documents or electronic records that may have been altered. This way, he can uncover the truth.