What is the minimum number of lines to separate the sets?

[![enter image description here][1]][1]

a) 2 b) 3 c) 4 d) 1 e) 5

Observe the graph below, it is possible to separate linearly with a line at least two of the classes?




[![enter image description here][3]][3]

a) Yes, just pass a straight line on the vertical axis.\
b) Yes, just pass a straight line on the horizontal axis.\
c) Yes, with all points separated. \
d) No, because the classes mix.\
e) No, because there are four quadrants.


How many circles are needed to group all points into three groups with 2
points and a group with 4 points?

[![enter image description here][2]][2]

a) 3 circles\
b) 5 circles\
c) 4 circles \
d) Points would remain\
e) There is no answer

I believe the answers are

 1. 3
 2. No, because the classes mix
 3. Points would remain

These challenges were proposed to me by a discreet math teacher and, as they are "challenges", I don't imagine that the answers are so simple.

[Source](https://www.amazon.com.br/Visual-Split-Puzzles-English-Kevin-ebook/dp/B08NYWW5VG/ref=sr_1_1__mk_pt_BR=%C3%85M%C3%85%C5%BD%C3%95%C3%91&dchild=1&keywords=visual+puzzle&qid=1609466327&sr=8-1)
  
[1]: https://i.sstatic.net/Xgwhi.png
  [2]: https://i.sstatic.net/QVhV4.png
  [3]: https://i.sstatic.net/5hyHS.png