TASK 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'.
PROBLEM: Question: To calculate the number of different genotypes in any allelic series the formula is applied: 
 Options:  <1> (n-1) / 2. <2> n x (n + 1) / 2. <3> n x (n-1) / 2. <4> (n-1) x (n + 1) / 2. <5> (2n-1) / 2.

SOLUTION: 2

PROBLEM: Question: It has been proven that amphetamines have reinforcing effects because: 
 Options:  <1> They are GABAergic agonists. <2> They are dopaminergic antagonists. <3> They are serotonergic antagonists. <4> They are dopaminergic agonists. <5> They are serotonergic agonists.

SOLUTION: 4

PROBLEM: Question: Regarding benign prostatic hypertrophy, it is NOT true that: 
 Options:  <1> Abdominal ultrasound is a non-invasive method to assess prostate size and post-voiding residual. <2> It can cause increases in PSA levels. <3> Rectal examination is a method to estimate prostate size. <4> Treatment with 5-alpha reductase inhibitors decreases symptoms. <5> It is a precancerous lesion.

SOLUTION:
5