Please select the eligibility criteria that correspond to the clinical trial below.
Title: Evaluation of The Effect of Fecal Microbiota Transplantation on Ulcerative Colitis and Its Mechanism
Brief Summary: Ulcerative colitis is a common digestive system disease, the incidence is increasing in recent years.It is reported that the occurrence and development of ulcerative colitis is closely related to imbalance of intestinal flora .Moreover,intestinal mucosal immunity may be related to intestinal flora. Fecal microbiota transplantation as a new technology to rebuild intestinal flora has been used for several disease，but the efficacy of ulcerative colitis by fecal microbiota transplantation needs to be further explored.


Options:
A: Inclusion Criteria:

* Age between 18 and 75 years
* Prior endoscopic confirmation of UC of at least 6 months AND with a minimum disease extent of 15 cm from the anal verge.
* Having active disease, defined with a Mayo Score between 4-10 and Mayo endoscopic subscore \>1
* Failure of conventional therapy or treatment with biologicals and / or small molecules.
* previous medical therapy:

  * oral 5-ASA compounds (5-ASA); stable dosing for 4 weeks before randomization;
  * Azathioprine, 6-Mercaptopurine (6-MP) or Methotrexate (MTX); stable dosing for 8 weeks before randomization;
  * Oral corticosteroid therapy (prednisone ≤ 20 mg/day or budesonide ≤ 9 mg/day); stable dosing for 2 weeks before randomization;
  * Topical therapy (foams, clysms) with mesalazine or budesonide: stable dosing for 2 weeks before randomization.
* previous vaccination against SARS-CoV-2 or previous SARS-CoV-2 infection or positive serology
* Ability to understand and willingness to sign informed consent document in patients whom the investigator believes can and will comply with the requirements of the protocol.
* Potentially childbearing patient: negative pregnancy test and use of a highly effective contraceptive method

Exclusion Criteria:

* Crohn's disease or indeterminate colitis or proctitis ulcerosa alone
* Acute abdomen or other clinical emergencies (e.g. toxic megacolon, fulminant gastrointestinal hemorrhage, ileus, perforation, etc.)
* Previous operations on the colon: colectomy, partial colon resections
* current gastrointestinal infections
* Congenital or acquired immunodeficiency
* severe comorbidity (e.g. insulin-dependent diabetes mellitus, decompensated liver cirrhosis, primary sclerosing cholangitis, renal impairment \> grade 2)
* diagnosis of a malignoma in the last 3 years
* refusal of endoscopies with video documentation
* No specific therapy for ulcerative colitis to date
* Lack of immunity to SARS-CoV-2
* Previous treatment with TNF-, IL12/IL23-, IL23- or integrin-antibodies within the last 8 weeks before randomisation
* Treatment with calcineurin inhibitors within the last 4 weeks before randomization
* Treatment with JAK inhibitors (e.g., tofacitinib, filgotinib, or upadacitinib) within the last 4 weeks prior to randomization
* Treatment with S1P receptor modulators (e.g. ozanimod, etrasimod) within the last 4 weeks before randomization
* Systemic antibiotic treatment within the last 8 weeks prior to randomization.
* Known intolerance of metronidazole or vancomycin
* Previous FMT or FMFT, previous participation in this study (screening allowed)
* Participation in a clinical trial within the last 3 months
* Use of probiotics in tablet, capsule, or powder form, or appropriate drinking yogurts (or similar) within 2 weeks prior to randomization
* Failure to ensure frozen storage of investigational products
* Addictive or other medical conditions or circumstances that do not allow the subject to appreciate the nature, significance, scope, and possible consequences of the clinical trial
* Indications that the patient would be unlikely to comply with the protocol (e.g., unwillingness to cooperate - compliance questionable)
B: Inclusion Criteria:

1. subjects voluntarily participate in the trial and sign informed consent;
2. sex is not limited,ranging from 18 to 75 years old;
3. meet the diagnostic criteria for ulcerative colitis in patients;
4. be able to communicate well with the researchers and follow the verification requirements.

Exclusion criteria:

1. Pregnancy or people who are not to give informed consent;
2. use of major immunosuppressive agents, including the use of large doses of glucocorticoids, calcineurin inhibitors, mTOR inhibitors, depleted lymphocyte biological agents, anti-tumor necrosis factor and other conditions; chemotherapy of antineoplastic drugs;
3. decompensated cirrhosis, progressive AIDS and HIV infectionor other serious immunodeficiency disease;
4. use of antibiotics and probiotics within six weeks;
5. with severe complications such as local stenosis, intestinal obstruction, intestinal perforation, toxic colon expansion, colon cancer, rectal cancer patients;
6. combined with cardiovascular, cerebrovascular, liver, kidney and hematopoietic system and other serious primary disease, mental illness.
C: Inclusion Criteria:

1. Patients aged 18 or over
2. Active UC defined as a Mayo score \> 3
3. A Mayo endoscopic score \> 0

Exclusion Criteria:

1. Participating in another clinical trial
2. Unable to give informed consent
3. Severe co-morbid medical illness
4. Concomitant Clostridium difficile infection
5. Severe UC requiring hospitalization.
6. Increase in medical therapy for UC in the last 12 weeks. Continued treatment with 5-ASA, azathioprine, 6-mercaptopurine or anti-TNF alpha therapy (e.g. infliximab) will be permitted if taken at stable dose for ≥12 weeks prior to randomization. Relapse on a stable dose (same dose for at least 2 weeks) or a tapering dose of steroids will also be permitted provided the dose of steroid is not increased again. Stable intake of probiotic therapy also permitted.
7. Antibiotic therapy in the last 30 days.
8. Pregnant women.
D: Inclusion Criteria:

Clinical diagnosis of Crohn's disease, with the diagnosis remaining unchanged after at least three months of follow-up.

Willingness to undergo FMT (Fecal Microbiota Transplantation).

Exclusion Criteria:

Presence of serious conditions that made them unsuitable for inclusion (e.g., malignant neoplasms, cardiopulmonary failure, serious liver or kidney disease).

Answer: B