According to john yoo's letter, a warrantless search or seizure is reasonable if:

a. the government's interests outweigh all other concerns.
b. google gives permission.
c. privacy concerns outweigh the government's interests.
d. the government's rights have been violated.

For the answer to the question above, The duty the government has that allows it to conduct warrantless searches and seizures is called the "emergency aid doctrine."Government interests are greater the need to keep certain information private. So the answer is A. The government's interests outweigh all other concerns.