**Core Concept**
The question tests the student's understanding of the **pharmacological effects of cannabis**, specifically the immediate physiological and psychological responses to its active component, **tetrahydrocannabinol (THC)**. Cannabis affects the **endocannabinoid system**, interacting with **cannabinoid receptors** in the brain and other parts of the body.

**Why the Correct Answer is Right**
Since the correct answer options are not provided, a general explanation will be given. An hour after inhalation of cannabis, the student is likely to experience effects such as **euphoria**, **relaxation**, **increased appetite**, and **altered perception**. The most immediate and noticeable effects typically include **dilation of the conjunctival blood vessels**, leading to **red eyes**, and **increased heart rate** due to the stimulation of the **sympathetic nervous system** by THC.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option text, it's impossible to provide a detailed explanation. However, incorrect options might include effects that are not typically immediate, such as long-term cognitive impairment or severe psychological disturbances, which are not usually seen an hour after inhalation.
**Option B:** Similarly, without the text, we can't specify why it's incorrect, but it might involve effects that are opposite to what is expected, such as decreased heart rate or immediate sobriety.
**Option C:** This option could be incorrect if it describes effects that are not associated with cannabis use, such as severe hallucinations or immediate physical dependence symptoms.
**Option D:** This might be incorrect if it suggests effects that are not typical for the timeframe, such as prolonged unconsciousness or immediate withdrawal symptoms.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the effects of cannabis can vary widely among individuals due to factors such as **dosage**, **method of consumption**, and **individual tolerance**. Understanding the potential for **variable effects** and being aware of the signs of **cannabis use disorder** are crucial for healthcare professionals.

**Correct Answer:** Correct Answer: D. Red eyes.