Answer :
The gauge pressure is determined by subtracting the ambient pressure from the absolute pressure. First, we have
$$
P_{\text{abs}} = 125.4 \, \text{kPa} \quad \text{and} \quad P_{\text{ambient}} = 99.8 \, \text{kPa}.
$$
The formula for gauge pressure is
$$
P_{\text{gauge}} = P_{\text{abs}} - P_{\text{ambient}}.
$$
Substituting in the values, we get
$$
P_{\text{gauge}} = 125.4 \, \text{kPa} - 99.8 \, \text{kPa} = 25.6 \, \text{kPa}.
$$
Thus, the gauge pressure inside the container is $\boxed{25.6 \, \text{kPa}}$, which corresponds to choice C.
$$
P_{\text{abs}} = 125.4 \, \text{kPa} \quad \text{and} \quad P_{\text{ambient}} = 99.8 \, \text{kPa}.
$$
The formula for gauge pressure is
$$
P_{\text{gauge}} = P_{\text{abs}} - P_{\text{ambient}}.
$$
Substituting in the values, we get
$$
P_{\text{gauge}} = 125.4 \, \text{kPa} - 99.8 \, \text{kPa} = 25.6 \, \text{kPa}.
$$
Thus, the gauge pressure inside the container is $\boxed{25.6 \, \text{kPa}}$, which corresponds to choice C.