**Core Concept**
The question refers to the concept of quartiles in statistics, specifically the first quartile (Q1). The first quartile is the value below which 25% of the data points fall.

**Why the Correct Answer is Right**
Given that the first quartile (Q1) is 34, this means that 25% of the observations are below 34. Therefore, the percentage of observations above this value would be the remaining 75%. This is because the first quartile divides the data into two parts: the lower 25% and the upper 75%.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not represent the correct percentage of observations above the first quartile.
**Option B:** Similarly, this option does not accurately represent the percentage of observations above the first quartile.
**Option C:** This option is also incorrect as it misrepresents the percentage of observations above the first quartile.

**Clinical Pearl / High-Yield Fact**
Remembering that quartiles divide data into four equal parts can help in understanding the distribution of data. The first quartile being at a certain value implies that 25% of data points are below this value, and thus, the majority (75%) are above it.

**Correct Answer:** C. 75%