Fuimos unas faldas, unos cinturones de marca, un vestido para juanita y un lente nuevo para mi cámara.

a) al supermercado y compramos
b) a la feria artesanal y compramos
c) al almacén y compramos
d) al mall y compramos

Option D) al centro comercial y compramos (centro comercial = mall)

Fuimos al centro comercial y compramos unas faldas, unos cinturones de marca, un vestido para Juanita y un lente nuevo para mi cámara.

Explanation:

The original sentence translated: "We went to [...] and we bought skirts, branded belts, a dress for Juanita and a new lens for my camera."

Option A) does not appear to be correct given that "supermercados" (supermarkets) usually sell food, beverages and household products.

Option B) is cleary not correct because camera lens are not handcrafted/handmade products "productos artesanales".

Option C) is incorrect because "almacén" (warehouse) is a place where goods are stored not sold.

It looks strange to me to say in Spanish "mall", I would rather use "centro comercial".

Native speaker over here. I hope this is helpful.