Final answer:
Phenylephrine and metaraminol are sympathomimetic drugs that act primarily on alpha adrenergic receptors, while methoxamine does not act on beta receptors even in high doses, and pseudoephedrine is an isomer of ephedrine.
Step-by-step explanation:
CD55 Sympathomimetics, such as phenylephrine, act as agonists at adrenergic receptors. Phenylephrine is an agonist primarily of the α1-adrenergic receptors and does not significantly affect beta receptors, confirming that option A is correct. Concerning option B, metaraminol also acts primarily on alpha receptors. However, for option C, methoxamine predominantly acts on alpha receptors and would not typically activate beta receptors even at high doses. Lastly, option D is accurate as ephedrine and pseudoephedrine are indeed stereoisomers of each other.