Please select the eligibility criteria that correspond to the clinical trial below.
Title: A Phase 2b, Multicenter, Randomized, Double Blind, Placebo-Controlled Clinical Trial to Evaluate the Efficacy of Short-Course Antimicrobial Therapy for Young Children With Acute Otitis Media (AOM) and Impact on Antimicrobial Resistance
Brief Summary: The investigators will study whether, in young children with acute otitis media (AOM), shortening length of antibiotic treatment as a strategy for reducing antimicrobial resistance provides satisfactory clinical outcome. This is a Phase 2b multicenter, randomized, double-blind, placebo-controlled clinical trial in 600 children aged 6 through 23 months comparing the efficacy of consistent reduced-duration antimicrobial treatment (5 days) with that of consistent standard-duration treatment (10 days) for each episode of AOM developing during a single respiratory season (October 1 through May 31).


Options:
A: Inclusion Criteria:

1. Aged 6 through 23 months
2. Have evidence of AOM defined as:

   * recent (within 48 hours) onset of signs and symptoms as described in the Acute Otitis Media - Severity of Symptoms (AOM-SOS) Scale AND a score of ≥3 at the time of enrollment on the AOM-SOS scale
   * middle ear effusion evidenced by the presence of at least 2 of the following:
   * decreased or absent mobility of the tympanic membrane
   * yellow or white discoloration of the tympanic membrane
   * opacification of the tympanic membrane

   AND
   * acute inflammation evidenced by one of the following:
   * 1+ bulging of the tympanic membrane with either intense erythema or otalgia
   * 2+ or 3+ bulging of the tympanic membrane
3. Has received at least 2 doses of pneumococcal conjugate vaccine
4. Parent has provided informed consent

Exclusion Criteria:

1. Toxic appearance \[capillary refill \>3 seconds, systolic blood pressure \<60 mm Hg\];
2. Inpatient hospitalization
3. Clinical or anatomical characteristics that might obscure response to treatment (tympanostomy tubes in place, cleft palate, or Down syndrome)
4. Sensorineural hearing loss (unilateral or bilateral)
5. Serious underlying systemic problems that might obscure response to infection (cystic fibrosis, neoplasm, juvenile diabetes)
6. Concomitant infection that would preclude evaluation of the response of the child's AOM to study product (pneumonia, periorbital cellulitis)
7. Acute wheezing exacerbation which may require treatment with systemic corticosteroids
8. Known renal or hepatic dysfunction or insufficiency
9. History of amoxicillin-clavulanate-associated cholestatic jaundice
10. Immune dysfunction or receipt of immunosuppressive therapy; chronic gastrointestinal conditions (i.e., malabsorption, inflammatory bowel disease)
11. Co-medications (systemic corticosteroids, more than one dose of systemic antimicrobial therapy within 96 hours, receipt of any investigational drug or vaccine within 30 days)
12. Hypersensitivity to penicillin, amoxicillin or amoxicillin-clavulanate, or phenylketonuria or known hypersensitivity to aspartame
13. Unable to complete study, or no access to phone
14. Previously enrolled in this study or currently enrolled in another study
B: Inclusion Criteria:

* Term infants with birth weight 2500-4500 gr
* Fed with breastmilk only or formula only before 2 months of age

Exclusion Criteria:

* Chronic illness
C: Inclusion Criteria:

* children aged 12-48 months attending educational program (either at nursery or primary school)

Exclusion Criteria:

* concomitant chronic/congenital diseases and disabilities,
* active tuberculosis,
* congenital cardiac defects,
* autoimmune diseases,
* immunodeficiency,
* chronic inflammatory bowel diseases,
* celiac diseases,
* cystic fibrosis,
* metabolic diseases,
* malignancy,
* chronic pulmonary diseases,
* malformation of the GI tract,
* history of allergy,
* severe wasting (less than 3 Standard deviations of weight-for-height z score),
* diarrhea on admission,
* antibiotic,
* pre/pro/symbiotic or immunostimulants use within 2 weeks before study start.
D: Inclusion Criteria:

* mother or father fo child with doctor diagnoses allergic disease

Exclusion Criteria:

* prematurity, major malformations

Answer: A