In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.

[EX Q]: Question: The recommended antibiotic treatment for acute diarrhea caused by Clostridium difficile is: 
 Options:  <1> Administer vancomycin orally. <2> Administer vancomycin intravenously. <3> Administer ciprofloxacin orally. <4> Administer metronidazole orally. <5> Administer rifaximin orally.
[EX A]: 4

[EX Q]: Question: Which of the nucleophiles listed below has a greater reactivity to the bimolecular nucleophilic substitution reaction? 
 Options:  <1> Hydroxide. <2> I last. <3> Ammonia. <4> Water. <5> Acetic acid.
[EX A]: 2

[EX Q]: Question: In the determination of water hardness due to the presence of Ca2 + and Mg2 + ions, the titrant reagent is used: 
 Options:  <1> Methyl orange. <2> A standard solution of potassium chloride. <3> Black Eriochrome T. <4> A standard solution of ethylenediaminetetraacetic acid (EDTA). <5> A solution of AEDT previously standardized against a solution of potassium phthalate.
[EX A]:
4