How long did the exposure take when the firts perminent photograph was taken?

In the above painting by salvador dalí, entitled persistence of memory, which of the following objects do not occupy positive space? a. the clocks c. the tree trunk b. the ground d. the cliff select the best answer from the choices provided

I'm dying: a couple going on vacation but his wife was on a business trip so he went to the destination first and his wife would meet him the next day. when he reached his hotel, he decided to send his wife a quick email. unfortunately, when typing her address, he mistyped a letter and his note was directed instead to an elderly preacher’s wife whose husband had passed away only the day before. when the grieving widow checked her email, she took one look at the monitor, let out a piercing scream, and fell to the floor in a dead faint. at the sound, her family rushed into the room and saw this note on the screen: dearest wife, just got checked in. everything prepared for your arrival tomorrow. p.s. sure is hot down here.

Who were the three patrons of the arts mention in this section of the lesson?