Please help due today

Which adverb of time best completes this sentence? yo estaba leyendo el periódico, mi padre estaba viendo el noticiero. a. aún b. mientras c. todavía d. entonces

Last one for it’s in english but it’s kinda tricky! i’m not sure if it’s b, so can someone . i’ll make brainliest

Ineed with spanish homework. translation of task: 11. fill out with the correct form of estar or hay 12. fill in fill with the verbs hay, estar and ser.