Answer: A. están.
Las tiendas están cerca del mercado.
The shops are close to the market.
Explanation: In Spanish, the verb "estar" is used to indicate the location of something. Since the subject in this sentence is "tiendas", that is a third-persona in the plural, the verb must be conjugated in this form. Las tiendas están.
High school escuela secundaria
It is yo trabajo because currently the verb is in infinity form but to put it in first person form you cross out the last two letters and add an o. So trabajar becomes yo trabajo.