Please select the eligibility criteria that correspond to the clinical trial below.
Title: A Phase 4 Randomized, Double-Blind, Placebo-Controlled, Multicenter Study Evaluating The Efficacy And Safety Of Re-Treatment With Varenicline In Subjects Who Are Currently Smoking, And Who Have Previously Taken Varenicline
Brief Summary: The main purpose of this study is to compare the effectiveness and safety of the re-treatment of smokers with varenicline with placebo for smoking cessation during the last 4 weeks of a 12 week course of treatment. The study will also assess whether smokers remain abstinent at Week 24 (12 weeks after the end of treatment) and Week 52 (40 weeks after the end of treatment).


Options:
A: Inclusion Criteria:

* Smokers aged 18 years or above and wanting to stop smoking
* Smokers who have smoked an average of at least 10 cigarettes per day over the last 4 weeks
* Smokers who have tried before to stop smoking at least once with varenicline, and who took varenicline for at least 2 weeks
* The last attempt to stop smoking must be at least 3 months before entering the study

Exclusion Criteria:

* Individuals who have not tolerated varenicline well previously, or who have a current or prior medical or psychiatric history that would make entry into the trial inadvisable
* Individuals who have previously participated in clinical trials of varenicline
* Individuals who have been participating in another smoking cessation trial within the last 3 months, or other drug trial within the last 30 days
B: Inclusion Criteria:

* Self-identified African American
* Smokes ≥ 1 cigarette per day (cpd)
* Smoke on ≥ 25 days of the past 30 days
* Functioning telephone
* Interested in quitting smoking
* Interested in taking 3 months of varenicline
* Willing to complete all study visits

Exclusion Criteria:

* Renal impairment
* Evidence or history of clinically significant allergic reactions to varenicline
* A cardiovascular event in the past month
* History of alcohol or drug dependence in the past year
* Major depressive disorder in the last year requiring treatment
* History of panic disorder, psychosis, bipolar disorder, or eating disorders
* Use of tobacco products other than cigarettes in past 30 days
* Use of pharmacotherapy in the month prior to enrollment, including prior use of varenicline
* Pregnant, contemplating getting pregnant, or breastfeeding
* Plans to move from Kansas City during the treatment and follow-up phase
* Another household member enrolled in the study
* Evidence of current severe major depressive disorder or suicidal ideation
C: Inclusion Criteria:

* Participant is a current smoker (≥ 10 cigarettes per day in the preceding\\ six months);
* Participant is willing to make a quit attempt in the 2-4 weeks after initial screening for eligibility;
* Participant is 18 years of age and older;
* Participant is willing to provide informed consent.

Exclusion Criteria:

* Participant is currently using or has used any intervention medications in the previous 6 months (i.e, Champix (varenicline); and/or Nicotine replacement therapy (patch, gum, inhaler, lozenge));
* Participant has contraindication(s) to any of the following smoking cessation medications:

  * Nicotine replacement therapy (allergic reaction to adhesive; serious cardiac arrhythmias (e.g., tachycardia); participant is during the immediate post-myocardial infarction period (i.e. incident has occurred within the last 10 days); severe or worsening angina pectoris; participant has had a recent cerebral vascular accident);
  * Varenicline (end-stage renal disease; use of cimetidine (by participants with severe renal impairment); previous allergic reaction to varenicline);
* Pregnant or breastfeeding women or those intending to become pregnant in the next year;
* Current or previous (in the last 3 months) substance abuse;
* Unable to provide informed consent due to unstable psychiatric symptoms (e.g., active, untreated psychosis or suicidality);
* Participant is unable to read and understand English or French;
* In order to prevent contamination across groups, only one person per household may participate.
D: Inclusion Criteria:

* Smokes at least 10 cigarettes per day
* Good general health
* Negative pregnancy test prior to study entry

Exclusion Criteria:

* Prior exposure to NicVAX or any other nicotine vaccine
* Known allergic reaction to alum or any of the components of the vaccine
* Use of systemic steroids, immunosuppressive agents or other medication that might interfere with an immune response
* Cancer or cancer treatment in the last 5 years
* HIV infection
* History of drug or alcohol abuse or dependence within 12 months
* Significant cardiovascular, hepatic, renal, psychiatric and/or respiratory disease
* Previous intolerance to varenicline
* Inability to fulfill all visits for approximately 54 weeks

Answer: A