Sentence 1: Sara's job now prohibits employees from using company's ice. 
 Sentence 3: Sara couldn't afford one of those thermos 
 Sentence 4:  Therefore, she bought the inexpensive one 
 Sentence 5:  Her drink stayed cold all day long like everyone else's 
 Option 1: Her coworkers bought expensive thermos that kept their drinks cold. 
 Option 2: Her coworkers kept water bottles in the office fridge.