Definition: 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'.
Input: Question: Acetylsalicylic acid is a compound whose pKa is 3.5. What percentage of a dose of this product can be absorbed in the stomach fasting (pH 1.5)? 
 Options:  <1> Less than 10% <2> Between 10% and 20%. <3> More than 90% <4> Between 20% and 40%. <5> 50%
