On April 17, 2013, an envelope addressed to President of the United States Barack Obama preliminarily tested positive for ricin.
Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request. ### Instruction: List the MITRE techniques contained in the text. ### Input: On April 17, 2013, an envelope addressed to President of the United States Barack Obama preliminarily tested positive for ricin. ### Response: .