Please select the eligibility criteria that correspond to the clinical trial below.
Title: Efficacy of Varenicline in Ambivalent Smokers
Brief Summary: The purpose of this study is to test whether Varenicline can help ambivalent smokers (those who are interested in quitting at some point in the future but have no current plans to quit) to reduce their smoking and eventually quit.


Options:
A: Inclusion Criteria:

* At least 18 years old
* Able to get to research lab in Burlington, Vermont or Omaha, Nebraska
* Daily smoker
* Smoke at least 8 cigarettes per day
* No reduction in smoking in last 30 days
* No intention to quit in the next 30 days
* Never used Varenicline before
* Not currently using smoking cessation medications or nicotine replacement therapy
* Willing to use Varenicline for at least 2 weeks
* Fluent in English

Exclusion Criteria:

* Cannot be currently pregnant or breastfeeding
* Kidney disease
* Frequent nausea
* On certain medications for asthma and/or depression
* Another household member in study
B: Inclusion Criteria:

* Stable clinical condition following a recent (\< 10 days) ACS event
* Active smoking status 30-days prior to ACS
* Age \> 21
* Life expectancy \>1 year

Exclusion Criteria:

I. Severe pulmonary disease (FEV1 \< 30% predicted ) II. End stage renal failure (eGFR \< 20 ml/min/m2) III. Uncontrolled depression or history of psychosis or bipolar disorder or active substance abuse IV. Uncontrolled stage IV hypertension V. Un-resolved life threatening arrhythmia VI. Planned surgical intervention (within \< 3 months) VII. Known hypersensitivity to study drug components VIII. Inability to comply with study protocol IX. Active malignancy other than basal cell carcinoma (BCC) X. End-stage congestive heart failure - NYHA IV or decompensated heart failure XI. Pregnancy or lactation
C: 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.
D: Inclusion Criteria:

* Outpatients, over legal age, smoking at least 10 cigarettes/day as a mean within the 2 months preceding the screening visit.

Exclusion Criteria:

* Patients who have taken an investigational drug within the past six months prior to the screening visit.
* Patients who had a previous quit attempt (= or \>1 day with the aid of pharmacological adjunct) in the previous three months (before screening).
* Patients who have smoked or consumed non-tobacco cigarettes or any form of tobacco product (other than cigarettes such as cigars, pipes, smokeless tobacco, etc) more than 3 times within the 3 months preceding the screening visit.
* Patients who currently present with (based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition \[DSM-IV\]):

  * Psychotic disorder
  * Major depressive episode
* Pregnant or breast-feeding women.
* Women of childbearing potential not protected by effective contraceptive method of birth control and/or who are unwilling or unable to be tested for pregnancy. Medically acceptable methods of birth control for this study include approved hormonal contraceptive medications or devices, approved intra-uterine contraceptive devices, use of two combined barrier methods.
* Patients who have suffered from a myocardial infarction, unstable angina or other major cardiovascular event within the past week prior to screening.
* Patients who have a history of multiple allergic reactions to medications in two drug classes.
* Patients who have QTcF \> 500 ms on the electrocardiogram (ECG).
* Patients with mild, moderate or severe renal impairment.
* Patients who have an abnormal laboratory test of potential clinical significance at screening.

Answer: A