Explanation:

Let’s break it down:

- Change in demand means people just stop wanting something—they move on, but this doesn’t always happen out of the blue. Sometimes it’s gradual or easy to predict.

- Natural calamities are sudden: floods, fires, earthquakes. They can ruin inventory out of nowhere. That's unexpected obsolescence—you had stock, now it’s useless.

- Change in technology is big. One day your device is hot, next day it’s not, because something way better just came out. That "out of nowhere" obsolescence hits hard and fast, often catching people off guard.

- None of these would be correct only if nothing here caused surprise obsolescence—but two definitely do.

The answer?

Option:3, Change in technology. That’s the classic case of unexpected obsolescence. Just look at what smartphones did to digital cameras, or streaming did to DVDs.