帰り道で雨に___、服がびしょびしょになった。
Q. Which form expresses 'got rained on'?
Translation
I got rained on on the way home and my clothes got soaked.
Explanation
The adversity passive 雨に降られる expresses being adversely affected by rain. 降って would need 雨が as subject, and 降らせる is causative ('make it rain').