Please select the eligibility criteria that correspond to the clinical trial below.
Title: Prevention of Vitamin D Deficiency in Breastfed Infants
Brief Summary: Breastfed infants living in a northern location (41 degrees N) are at high risk of vitamin D deficiency during winter. This trial is designed to determine how much supplemental vitamin D breastfed infants need to receive in order to remain free of vitamin D deficiency


Options:
A: Inclusion Criteria:

* Term infant
* No major congenital malformations
* Less than one month old
* Breastfed, no other foods

Exclusion Criteria:

* Formula feeding
* Premature birth
B: Inclusion criteria

* Currently lactating mothers at least 18 years of age
* Willing to continue exclusively breastfeeding their infant throughout the study interval
* The infant is 1-6 months of age at the beginning of the study
* Willing and able to participate in all aspects of the study
* Mother and infant are in good health, as determined by the study investigator
* Have been provided with, understand, and have signed the informed consent for themselves and their child.

Exclusion criteria

* Have recently travelled (within the preceding 30 days) or plan to travel south of 35 degrees north latitude during the study interval
* Have recently or plan to engage in indoor tanning
* Are currently taking medications that affect vitamin D metabolism, like steroids, anticonvulsants, or barbiturates
* Are nursing multiple infants (e.g. twins)
* Are taking greater than the daily recommended intake of 1000 mg elemental calcium as calcium supplements
* Are taking greater than the standard daily dose of 400 IU of vitamin D found in prenatal vitamins
* Infant weight below 1.67 kg
* Mothers with baseline 25(OH)D levels \>70 ng/ml, and/or infants with baseline 25(OH)D levels \>70 ng/ml
* History of kidney stones
C: Inclusion Criteria:

* Women aged 18 years and above.
* Gestational age of 17 to 24 completed weeks estimated based on recalled last menstrual period (LMP) and/or ultrasound.
* Intends to permanently reside in the trial catchment area for at least 18 months.

Exclusion Criteria:

* History of medical conditions that may predispose the participant to vitamin D sensitivity, altered vitamin D metabolism and/or hypercalcemia, or history of renal calculi.
* High-risk pregnancy based on one or more of the following findings by point-of-care testing:

  * Severe anemia: hemoglobin \<70 g/L assessed by Hemocue
  * Moderate-severe proteinuria: ≥ 300 mg/dl (3+ or 4+) based on urine dipstick
  * Hypertension: systolic blood pressure ≥140 mm Hg and/or diastolic blood pressure ≥90 mm Hg
* Multiple gestation, major congenital anomaly, or severe oligohydramnios based on maternal history and/or ultrasound.
* Unwillingness to stop taking non-study vitamin D or calcium supplements or a multivitamin with calcium and/or vitamin D.
* Currently prescribed vitamin D supplements as part of a physician's treatment plan for vitamin D deficiency.
* Previous participation in the same study.
D: Inclusion Criteria:

* Healthy singleton term born infants of appropriate size for gestational age (AGA) according to the Centers for Disease Control growth charts based on weight at birth between the 5th and 95th percentiles for sex; and born to healthy breastfeeding women. This allows us to assess growth and bone mineral accretion without bias of intrauterine growth restriction.

Exclusion Criteria:

* Infants of mothers with history of gestational diabetes or hypertension in pregnancy; chronic alcohol use; malabsorption syndromes due to malabsorption of vitamin D (celiac disease, Crohn's etc.); and multiple births.
* Should any exclusion criteria be identified after recruitment, the infant will be excluded from the main analyzes, but followed in a separate arm as intent-to-treat.

Answer: A