The correct answer is C. Isotretinoin.

This patient has scarring nodulocystic acne. This is best treated with isotretinoin to prevent further acne scarring as acne scarring lasts forever. Early treatment of acne is essential for the prevention of lasting cosmetic disfigurement due to scarring. Erythema and postinflammatory hyperpigmentation often persist after resolution of inflammatory acne lesions. Although the pigmentary changes usually fade over many months if the acne is brought under control, occasionally they can be permanent. Unfortunately, pitted scars  or hypertrophic scars (most commonly on the trunk) are often sequelae of nodulocystic acne.

Topical tretinoin: The anti-acne activity of topical retinoids involves normalization of follicular keratinization and corneocyte cohesion, which aids in the expulsion of existing comedones and prevents the formation of new ones.

Minocycline: Minocycline is an oral antibiotic treatment that can be used in the treatment of acne however it is not the optimal choice in preventing cosmetic disfigurement due to scarring.

Spironolactone: Spironolactone functions as both an androgen receptor blocker and an inhibitor of 5α-reductase. In doses of 50–100 mg twice daily, it has been shown to reduce sebum production and improve acne however it does not prevent or treat scarring.

Bactrim: Bactrim is an oral antibiotic treatment that can be used in the treatment of acne however it is not the optimal choice in preventing cosmetic disfigurement due to scarring.

References: Guadanhim LR, Gonçalves RG, Bagatin E. Observational retrospective study evaluating the effects of oral isotretinoin in keloids and hypertrophic scars. Int J Dermatol. 2016 Nov;55(11):1255-1258. doi: 10.1111/ijd.13317. PMID: 27419807