Statements : No mat is fan. Some fans are cars. All cars are shirts.

Conclusions :
I. All mats are cars.
II. All shirts are cars.
III. Some shirts are fans.
IV. No shirt is a mat.

In the given statements:
Statements :
No mat is fan.
Some fans are cars.
All cars are shirts.
Conclusions :
I. All mats are cars. - False. There is no direct relationship established between mats and cars in the statements. Hence, conclusion I does not follow.
II. All shirts are cars. - True. Since all cars are shirts, this conclusion follows from the given statements.
III. Some shirts are fans. - False. There is no direct relationship established between shirts and fans in the statements. Hence, conclusion III does not follow.
IV. No shirt is a mat. - True. Since no mat is a fan and some fans are cars, which are shirts, it implies that no shirt is a mat. Therefore, conclusion IV follows.
Hence, the correct answer is Option C: Only IV follow.