b) to mountain-bike
since the sentence follows along with to run and to swim the answer has to be "to mountain-bike".
Answer:
The most appropriate action to take for the investigator is to send a copy of the informed consent via facsimile to the subject's wife. After she has had the opportunity to speak to the investigator, she can sign the informed consent and fax it back
Explanation:
Since the elderly man doesn't have the legal right to authorize any kind of process, his wife who is his representative get the information and sign the papers before taking action into a treatment besides being an experimental treatment must make it more dangerous and the decision requires more analysis and permissions.
The part of the letter that needs revision in order to be an appropriate formal letter is the salutation. A letter should always include a salutation other than just writing the name of the person. The salutation should be brief, but it helps to introduce the message that needs to be delivered without setting a rude or sharp tone.