Stupid Mistake

This is seriously a stupid mistake, and I can't believe that the EOY paper of this school actually got printed out like this. But to thank them for giving us the paper, this should just be some insider joke that's not disclosed to the public.

Study Source A

Source A: A screenshot of a school EOY paper

Qns 1a: Why is there a white patch?

Study Source B

Source B: Another screenshot of the same page

Study Source C

Source C: Now a ruler is added as a reference to the same screenshot

Qns 1b: Compare sources B and C. What are the sources trying to say?

Highest level answer:
1a) Source A has a white patch because it censors the school name. This can be seen in source B, where the school name is at the location of the white patch, which shows that the school name is censored in Source A. The purpose of the source is to show everyone what the EOY paper looked like, but at the same time, do not spoil the school's reputation. This is known because the setter of this question received the EOY paper from another school and feels very grateful to the school. Hence, he censors the bit.

1b) Sources B and C differ as Source B has no ruler whereas Source C has a ruler placed on it. This is clearly true as we do not find any trace of a ruler on Source B. This proves that it is impossible to have a ruler in source B, be it transparent, invisible or whatever forms of a ruler that does not block your vision. However, there is a distinct ruler on Source C. This proves the existence of the ruler in source C, and not because the setter of this question used illusionary effects or any form of magic trick. Source B and C differ in purpose. Source B shows the stupid mistake which is mentioned in the background information. However, some people may claim that this was due to scanning errors. Source C supports source B by having a ruler, this ruler traces the straightline down to the words below, some of which are covered by the ruler, showing that there are no scanning errors. Hence, sources B and C differ in purpose because source B shows the mistake and source C supports source B.

I hope everyone had fun reading this.