Explanation:
cocktail or martini is "bruised" when it's been over-shaken, adding slivers of ice and oxygen bubbles to the drink that give it a murky or cloudy appearance. Among pros, bruising cocktails is considered the mark of an amateur.
The answer is C.
The story says, "Then, gently put the valve of the tube through the hole in the rim and insert the rest of the tube into the tire, being careful not to twist it."