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:

* Subjects must have smoked an average of at least 10 cigarettes per day during the past year and over the month prior to the screening visit, with no period of abstinence greater than 3 months in the past year.

Exclusion Criteria:

* Subjects who have used bupropion (Zyban, or Wellbutrin) previously.
C: Inclusion Criteria:

* Men and women
* 18 to 75 yrs old
* Motivated to stop smoking
* Smoke at least 10 cigarettes/day

Exclusion Criteria:

* Active psychiatric disease
* Severe or unstable cardiovascular or pulmonary disease
* Current or recent treatment to stop smoking
* Previous use of varenicline
D: Inclusion Criteria:

* Smoker of at least 10 cigarettes daily
* Motivated to quit smoking
* Reports at least one unsuccessful attempt to quit in the last 2 years
* In generally good health
* Provides written informed consent to participate in the sudy

Exclusion Criteria:

* Pregnant or nursing females.
* Women of child-bearing potential must agree to use acceptable contraceptive precautions (contraceptive pill and one barrier method)during the study and for 2-months thereafter
* History of anaphylaxis
* History of alcohol or drug abuse
* History of or current significant medical or psychiatric disorder
* History or presence of cataract or abnormality identified by slit lamp investigation
* Use of other MAO inhibitors, pethidine, SSRIs, tricyclic antidepressants,nasal or oral decongestants or cold medicines containing ephedrine, pseudoephedrine or other sympathomimetics.
* Any medicine contraindicated for use with MAO inhibitors.
* Have or be a carrier of hepatitis B or c or HIV 1 or 2
* Use of tobacco products other than cigarettes
* Use of nicotine replacement therapy in the past month
* Received an investigational drug in the past 30 days
* Previous participation in a study with a MAO-B inhibitor

Answer: A