**Core Concept**
The enamel color of primary and permanent teeth is determined by the presence of pigments such as melanin and porphyrins. The enamel color is also influenced by the transparency and thickness of the enamel.

**Why the Correct Answer is Right**
The enamel color of primary teeth is generally whiter and more translucent than that of permanent teeth. This is due to the differences in the composition and thickness of the enamel. Primary teeth have a thinner and more porous enamel, which allows more light to pass through and gives them a whiter appearance. In contrast, permanent teeth have a thicker and more compact enamel, which scatters light and gives them a more yellowish appearance.

**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect as primary teeth are not yellowish in color.
**Option B:** This is incorrect as permanent teeth are not white in color.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the enamel color can be affected by various factors such as age, diet, and oral hygiene. Additionally, some medical conditions such as fluorosis can cause changes in the enamel color.

**Correct Answer: C. White and Yellowish respectively.**