Task: Question Answering
Input (English): Question: What factors depends on the apparent volume of distribution of a drug ?: 
 Options:  <1> Its degree of binding to plasma and tissue proteins and its elimination half-life. <2> Of its distribution coefficient and its elimination half-life. <3> Of its elimination half-life and its elimination constant. <4> Its degree of binding to plasma and tissue proteins and their distribution coefficient. <5> Of its constant elimination and its clearing.
Output (English): 4