Option A. should be the correct answer, that is E-reader.

Virtual reality headset doesn't even operate in an lighting condition, it works void of any kind/form of lighting condition.

But the E-reader which is primarily meant for reading primarily use e-ink displays. E-ink technology mimics the appearance of ordinary ink on paper. Which means unlike the traditional screen used for our gadgets (laptops and phones) for an E-reader, the brighter the light, the better the writings, just like how the more light falls on a white paper with writings, the more clearer the writing becomes.