Please select the eligibility criteria that correspond to the clinical trial below.
Title: Can Rhodiola Crenulata Intake Improve Oxygen Saturation and Decrease the Incidence of Acute Mountain Sickness.
Brief Summary: Traditional folk medicine in the Arctic and Himalayan areas used Rhodiola species to enhance physical endurance, prevent aging, resist acute mountain sickness (AMS), and to treat fatigue, depression, anemia, impotence and respiratory infections. Rhodiola crenulata are widely used to prevent AMS in Himalayan areas and Lhasa in Tibet but none was examined by human study. The investigators conducted a randomized, double blind, placebo controlled, crossover study to investigate the efficacy of Rhodiola crenulata in preventing AMS.


Options:
A: Inclusion Criteria:

* age between 20 and 55 years.
* able to complete the study protocol of 9-day study regimens and mountain climbing twice.
* no prophylactic medication or herb one month before ascent.
* maintaining the same living conditions and habits four months before the first mountain climbing and four months between two mountaineering.

  * living in the same altitude or within a difference of 200 meters.
  * no additional physical training.
  * no plan to gain or loss weight.
  * no altitude exposure above 2500m.

Exclusion Criteria:

* any history of chronic obstructive pulmonary disease, heart failure, cerebral neoplasm, mania, renal or hepatic insufficiency.
* women in pregnancy or intending of pregnancy during the 4-month study period.
B: Inclusion Criteria:

* Chronic obstructive pulmonary disease (COPD), GOLD grade 1-2
* Living at low altitude (\<800m)

Exclusion Criteria:

* COPD exacerbation
* severe COPD, GOLD grade 3 or 4
* arterial oxygen saturation \<92% at low altitude (\<800 m)
* Diabetes, uncontrolled cardiovascular disease such as systemic arterial hypertension, coronary artery disease; previous stroke; pneumothorax in the last 2 months, untreated or symptomatic peptic ulcer disease, glaucoma, obstructive sleep apnea.
* Internal, neurologic or psychiatric disease that interfere with protocol compliance including current heavy smoking (\>20 cigarettes per day).
* pregnant or nursing patients
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:

* 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.

Answer: A