Match the following drugs with their therapeutic actions:
(i) Ranitidine                                        (a) Antidepressant
(ii) Nardil (Phenelzine)                        (b) Antibiotic
(iii) Chloramphenicol                           (c) Antihistamine
(iv) Dimetane (Brompheniramine)   (d) Antacid
                                                                (e) Analgesic

First, we recall the therapeutic use of each drug from standard medicinal chemistry facts.

We have Ranitidine. It is well known that Ranitidine blocks the $$\mathrm{H_2}$$-histamine receptor present on the gastric parietal cells, thereby reducing gastric acid secretion. A drug that decreases stomach acidity is termed an antacid. So Ranitidine corresponds to $$\text{(d) Antacid}$$.

Now consider Nardil, whose generic name is Phenelzine. Phenelzine belongs to the class of monoamine oxidase inhibitors, abbreviated as $$\text{MAOIs}$$. Drugs that inhibit MAO increase the levels of neurotransmitters such as serotonin and norepinephrine, and are therefore used to treat depressive disorders. Hence Nardil (Phenelzine) matches $$\text{(a) Antidepressant}$$.

Next, we examine Chloramphenicol. From general pharmacology, Chloramphenicol is a broad-spectrum antibiotic that inhibits the $$50\text{ S}$$ ribosomal subunit and blocks peptide-bond formation in bacteria. Therefore its therapeutic action is clearly $$\text{(b) Antibiotic}$$.

Finally, we look at Dimetane, whose active ingredient is Brompheniramine. Brompheniramine competitively antagonises the $$\mathrm{H_1}$$-histamine receptor, giving relief from allergic symptoms such as sneezing and itching. A medicine that blocks histamine in this way is called an antihistamine, that is, $$\text{(c) Antihistamine}$$.

Collecting all four pairings we obtain the set of matches in symbolic form:

$$$ \begin{aligned} (i)&:&\; \text{Ranitidine} &\longrightarrow& (d) \; \text{Antacid}\\ (ii)&:&\; \text{Nardil (Phenelzine)} &\longrightarrow& (a) \; \text{Antidepressant}\\ (iii)&:&\; \text{Chloramphenicol} &\longrightarrow& (b) \; \text{Antibiotic}\\ (iv)&:&\; \text{Dimetane (Brompheniramine)} &\longrightarrow& (c) \; \text{Antihistamine} \end{aligned} $$$

Comparing these matches with the given options, we notice that Option B lists exactly the same correspondence, namely $$$ (i)-(d),\; (ii)-(a),\; (iii)-(b),\; (iv)-(c) $$$. No other option satisfies every pairing simultaneously.

Hence, the correct answer is Option B.