**Core Concept**
After 28 weeks of gestation, the fetus has reached a stage of development where it is considered viable, has a birth weight of more than 1000 grams, and has matured to the point where it can produce surfactant, which is essential for lung expansion and gas exchange. This period marks a critical transition in fetal development, where the likelihood of survival outside the uterus increases significantly.

**Why the Correct Answer is Right**
The fetus at 28 weeks of gestation has reached a stage of maturity where it is considered viable due to the development of essential organs and systems. The birth weight of the fetus is typically over 1000 grams, which is a critical threshold for viability. Additionally, type II pneumocytes, responsible for producing surfactant, are present and functional, enabling the lungs to expand and facilitate gas exchange after birth. The presence of surfactant is a key indicator of lung maturity and a critical factor in the transition from fetal to neonatal life.

**Why Each Wrong Option is Incorrect**
**Option A:** While the term "viable" is used to describe the fetus at 28 weeks, it is essential to note that viability is not solely determined by gestational age but also by the presence of other factors, such as the presence of surfactant and the development of essential organs. However, in the context of this question, "viable" is a correct descriptor.

**Option B:** While a birth weight of more than 1000 grams is a general indicator of viability, it is essential to note that there can be significant variability in fetal growth and development. Some fetuses may be smaller or larger than 1000 grams and still be viable.

**Option C:** Type II pneumocytes are indeed present at 28 weeks of gestation, but this option is incorrect because it is not a standalone indicator of viability. The presence of type II pneumocytes is essential for lung maturity, but it must be considered in conjunction with other factors, such as birth weight and the development of essential organs.

**Clinical Pearl / High-Yield Fact**
A key clinical consideration at 28 weeks of gestation is the presence of surfactant, which is essential for lung expansion and gas exchange. The ability to produce surfactant is a critical indicator of lung maturity, and its absence or dysfunction can lead to respiratory distress syndrome in newborns.

**✓ Correct Answer: D. All**