In a completely opaque medium, if $50\%$ of the incident monochromatic radiation is absorbed, then which of the following statements are $CORRECT$
- $50\%$ of the incident radiation is reflected
- $25\%$ of the incident radiation is reflected
- $25\%$ of the incident radiation is transmitted
- No incident radiation is transmitted
- $P$ and $S$ only
- $Q$ and $R$ only
- $P$ and $Q$ only
- $R$ and $S$ only