**Core Concept**
The question tests the understanding of the differences in cardiac actions of epinephrine and norepinephrine, two catecholamine hormones with distinct effects on the heart. Both hormones stimulate the heart through beta-adrenergic receptors, but they have varying effects on cardiac contractility and chronotropy.

**Why the Correct Answer is Right**
Epinephrine (adrenaline) has a more pronounced effect on the heart compared to norepinephrine (noradrenaline). This is because epinephrine has a higher affinity for beta-1 receptors, which are predominantly found in the heart. Stimulation of beta-1 receptors increases cardiac contractility and heart rate (chronotropy). In contrast, norepinephrine has a higher affinity for alpha-1 receptors, which causes vasoconstriction and increases blood pressure. As a result, epinephrine has a more significant impact on cardiac contractility and chronotropy compared to norepinephrine.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify the correct difference between epinephrine and norepinephrine's cardiac actions. While both hormones do increase heart rate and contractility, the question asks for the "most striking difference."
* **Option B:** This option is incorrect because it does not accurately describe the cardiac actions of either epinephrine or norepinephrine. Epinephrine and norepinephrine both increase cardiac contractility and heart rate, but the question asks for the difference between their effects.
* **Option C:** This option is incorrect because it does not specify the correct difference between epinephrine and norepinephrine's cardiac actions. While both hormones do have some similar effects on the heart, the question asks for the "most striking difference."

**Clinical Pearl / High-Yield Fact**
When administering catecholamine hormones like epinephrine and norepinephrine, it is essential to consider their distinct effects on the heart. Epinephrine is often used in cardiac arrest situations where increased cardiac contractility and heart rate are necessary. In contrast, norepinephrine is often used in septic shock to increase blood pressure through vasoconstriction.

**Correct Answer: B. Norepinephrine has a more pronounced effect on peripheral vascular resistance compared to epinephrine.**