Chinese Test: What does “白 (bái)” refer to in Chinese?

Beginner Level 初级 (chūjí)

Gānggāng diànnǎo sǐjī le, wǒ de gōngzuò quán dōu bái gàn le. 刚刚            电脑   死机了,我 的    工作       全    都   白 干 了。

What does “白 (bái)” refer to in the above context?

A. White B. In vain C. Black

See Answer