Concept:The gap is filled by the past participle of the verb “loose” because “will get” is used as a future passive form.
Explanation:“Loose” means to release or to make something less tight.
Its past participle is “loosed”.
After “will get”, a past participle is required to show what will happen to the subject.
So “will get loosed” means “will be released” or “will become untied”.
“loose” is an adjective and also the base form of the verb, so it cannot take this position in the passive structure.
“lose” means to misplace or fail to keep, which does not fit the meaning.
“loosing” is the present participle and cannot follow “will get” in this sense.
Answer:C. loosed