Please select the eligibility criteria that correspond to the clinical trial below.
Title: A Randomized Controlled Trial of the Effects of Tadalafil and Dexamethasone Versus Placebo on Pulmonary Edema Formation and Cerebral Blood Flow Autoregulation in High Altitude Newcomers With a Previous History of High Altitude Pulmonary Edema
Brief Summary: A double-blind placebo controlled study

* To compare the effect of tadalafil and dexamethasone versus placebo on Ppa and pulmonary edema formation in subjects susceptible to HAPE.
* To investigate the effect of dexamethasone on alveolar fluid clearance, as assessed by measurement of the nasal potential difference, and prevention of HAPE.
* To investigate the effect of the tadalafil and dexamethasone versus placebo on the dynamic CBF autoregulation properties and on the development of AMS in HAPE susceptible subjects.


Options:
A: Inclusion Criteria:

* normotensive (i.e. \<140/90 mmHg)

Exclusion Criteria:

* Pregnancy
* nursing mother
* current tobacco use or regular use within the previous two years
* use of prescription medication other than birth control
* asthma or any other type of lung/respiratory dysfunction
* resting oxygen saturation \<95%
* unwillingness to abstain from exercise for 48 hours prior to laboratory testing
* use of anticoagulant therapy or have a known or suspected bleeding disorder
* identification of contraindication during screening (i.e. positive stress test)
* any history of mountain sickness (altitude sickness)
* any history of allergic reaction, hypersensitivity or idiosyncratic reaction to any of the products administered during the study, including allergy to any sulfa or sulfonamide derivatives
* history of clinically significant illness within 4 weeks prior to Day 1
* Subjects who have made any significant donation (including plasma) or have had a significant loss of blood within 30 days prior to visit 1
* receipt of a transfusion or any blood products within 30 days prior to visit 1.
B: Inclusion Criteria:

* At least one previous episode of high altitude pulmonary edema

Exclusion Criteria:

* pulmonary arterial hypertension
* congenital heart disease
* any chronic lung disease
C: Inclusion Criteria:

* Permanent residence at low (\<500 m) altitude
* Conventional systolic BP (average of two measurements) 140-159 mmHg or conventional diastolic BP 90-99 mmHg in subjects untreated or after 4 weeks of washout
* Mean daytime systolic BP ≥135 and \<150 mmHg and/or mean daytime diastolic BP ≥85 and \<95 mmHg in subjects untreated or after 4 weeks of washout
* Written informed consent to participate in the study

Exclusion Criteria:

* Conventional systolic BP (average of two measurements) ≥150 mmHg and conventional diastolic BP ≥95 mmHg in treated subjects
* Regular use of two or more antihypertensive drugs (with the exception of subjects on two antihypertensive drugs in low doses)
* Treated antihypertensive subjects in whom withdrawal of treatment is deemed unethical by the investigator (e.g. because of the existence of compelling indications other than hypertension for continuous use of previously used antihypertensive agent)
* Contraindications (including a history of adverse reactions) to angiotensin receptor blockers or calcium antagonists
* History of serious mountain sickness
* Subjects who over 3 months preceding inclusion in the study spent considerable (\> 1 week) amount of time at altitudes above 2500 m.
* Cardiovascular diseases other than hypertension (coronary heart disease, heart failure, atrial fibrillation, valvular or congenital heart disease, cardiomyopathies, cerebrovascular disease, peripheral artery disease, aortic aneurysm)
* Suspected or confirmed secondary hypertension
* Diabetes mellitus
* Serious respiratory disorders
* Other conditions deemed relevant by the investigator (including liver disease, renal disease, thyroid disorders)
* BMI ≥35 kg/m2
* Upper arm circumference \>32 cm
* known severe obstructive sleep apnea (apnea-hypopnea index \> 30 or use of CPAP) or excessive daytime sleepiness (Epworth Sleepiness Scale \> 10)
* Pregnancy
* Premenopausal women not using effective contraceptive methods
* Elevated probability of noncompliance with the study procedures
D: Inclusion Criteria:

* Healthy, physically fit subject
* Mountaineering experience

Exclusion Criteria:

* Any type of cardiac or respiratory disease
* Regular intake of any medication
* History of high altitude pulmonary oedema
* Severe acute mountain sickness at altitudes below 3500m or high altitude cerebral oedema.

Answer: B