Task: Question Answering
Input (English): Question: In the filtration process, the flow velocity is: 
 Options:  <1> Directly proportional to the quantity of the cake deposited. <2> Directly proportional to the amount of materials in suspension. <3> Dependent on the degree of ionization of the substance to be filtered. <4> Dependent on the ambient temperature. <5> Inversely proportional to the quantity of the cake deposited.
Output (English): 5