Please select the eligibility criteria that correspond to the clinical trial below.
Title: Effects of an Extended Period of Varenicline Use Prior to Quitting Smoking on Post-quitting Urges to Smoke
Brief Summary: Varenicline (Champix) is a relatively new medicine that is effective in helping people to quit smoking. It is normally started 1-week before stopping smoking and used for up to 12-24 weeks. We are trying to find out if using varenicline for an extended time (4-weeks) before stopping smoking is better than the standard 1-week of use prior to stopping.

The study will recruit 100 smokers who want to stop. They will be randomly allocated to receive varenicline(4-weeks) or placebo (3-weeks followed by 1-week of active treatment as indicated by standard prescribing practice), followed by a 12-week open label treatment period where all participants will receive varenicline.


Options:
A: Inclusion Criteria:

* Smokers seeking treatment
* Aged 18 and over
* Consenting to take part in the trial

Exclusion Criteria:

* Pregnant or breastfeeding
* End-stage renal disease
* Used varenicline in the past 6 months
* Unable to fill in questionnaires in English
* Current psychiatric illness
* Current serious illness including uncontrolled hypertension and recent cardiac event
* Sensitivity to varenicline currently enrolled in other research projects.
B: Inclusion Criteria:

* Age 14-21
* Daily smoker for ≥6 months
* Desire to quit smoking, with at least one prior failed quit attempt and willingness to participate in a treatment study
* If under age 18, parent(s) or guardian(s) able to participate in informed consent and initial assessment (unless the participant provides evidence of emancipated status)
* If female, agreement to use birth control (any form of hormonal contraception such as Depo-Provera, daily oral contraception, transdermal patch, or Nuva-ring; intrauterine device; sterilization; or double barrier contraception, which is a combination of any two of the following methods: condoms, spermicide, diaphragm) to avoid pregnancy

Exclusion Criteria:

* Lifetime history of any DSM-IV-TR mood or psychotic disorder (e.g., major depressive disorder, bipolar disorder, schizophrenia)
* Lifetime history of suicidality, homicidality, or clinically significant hostility/aggression
* Current substance dependence, other than nicotine
* Current unstable major medical disorder
* Current pregnancy or breastfeeding
* Current use of medications with smoking cessation efficacy
* Known hypersensitivity to varenicline
C: Inclusion Criteria:

* Male or female daily smokeless tobacco users aged 18 years and older, who are motivated to stop use of all tobacco products.
* Subjects must be daily users of nicotine containing smokeless tobacco and using smokeless tobacco on at least 8 occasions per day averaged over a week.
* Have used smokeless tobacco for at least 1 year prior to screening with no period of abstinence \>3 months in the past year.

Exclusion Criteria:

* Subjects using nicotine containing products (including smoking tobacco) other than smokeless tobacco for 3 months prior to screening.
* Subjects with exhaled Carbon Monoxide (CO) \>10 ppm at baseline.
* Subjects who have used varenicline, bupropion, or NRT within 3 months of screening.
* Subjects currently or within the past 12 months requiring treatment for depression or have a current or prior history of panic disorder, psychosis, bipolar disorder or any other serious mental illness.
D: 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

Answer: A