The answer would be C. estuvo. Because although est<span>á is a conjunction of star and it is in the la/el/ud form it's in the present tense and the question is asking where was Beatriz yesterday (yesterday meaning past tense) so estuvo (which is preterite of estar in el/la/ud form) would be the answer. Hope this helps!</span>
Durante la fiesta había* fuegos artificiales.