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'.
--------
Question: Question: Enzymatic regulation by phosphorylation: 
 Options:  <1> It is reversible. <2> It requires enzymes that directly introduce the Pi. <3> Introduce the Pi into acidic and basic amino acids. <4> Always activate enzymes. <5> It is carried out by phosphatases.

Answer: 1


Question: Question: The reaction of an alkene with metachloroperbenzoic acid causes a cyclic ether which is called: 
 Options:  <1> Furano <2> Dioxane <3> Epoxide <4> Azirano <5> Lactone

Answer: 3


Question: Question: What is the purpose of the phthalyl group in phthalisulfatiazole ?: 
 Options:  <1> Improve intestinal absorption. <2> Prevent intestinal absorption. <3> Improve the passage through the blood-brain barrier. <4> Prevent passage through the blood-brain barrier. <5> Increase the affinity towards the therapeutic target of the drug.

Answer:
2