The given sentences, when properly sequenced, form a coherent paragraph about system administrators reacting to major security flaws named Meltdown and Spectre. Sentence 1 is fixed as the opening. Choose the most logical order of sentences A, B, C, and D.

Introduction / Context:
This parajumble is about system administrators reacting with dark humour to the discovery of serious security flaws. You must arrange the labelled sentences so that they form a clear narrative, starting from sentence 1 about an online forum where sysadmins are sharing gallows humour.

Given Data / Assumptions:
Sentence 1 sets the scene on an online forum. Sentence A explains that they were discussing two security flaws called Meltdown and Spectre that affect any computer powered by processors from major chip designers. Sentence D clarifies that this means most modern devices, from smartphones to cloud servers. Sentences C and B then present two examples of gallows humour: one sysadmin posts a picture of a fire raging in a skip, and another jokes that computers were a mistake.

Concept / Approach:
A good paragraph first names the topic of discussion, then explains how big the problem is, and finally illustrates it with concrete examples and jokes. The sequence should move from general to specific and from factual explanation to humorous reaction. Pronouns like they must also have a clear antecedent in the immediately preceding context.

Step-by-Step Solution:
First, sentence A should follow sentence 1 because it answers the natural question what were they discussing. It specifies the flaws Meltdown and Spectre and notes that they affect machines using processors from Intel, AMD, ARM, and others.Second, sentence D logically comes after A because it unpacks the phrase that is most of them by listing examples such as smartphones, desktop PCs, game consoles, and cloud machines. This extends the explanation of the scale of the problem.Third, once the seriousness of the issue is established, sentence B can introduce one example of gallows humour in words, where someone comments that computers were a mistake.Fourth, sentence C then gives another humorous example, this time visual, where one user simply posts a picture of a fire raging in a skip. The two jokes together illustrate the mood described in sentence 1.Thus the most coherent order after sentence 1 is A, then D, then B, then C, which corresponds to the answer ADBC.

Verification / Alternative check:
Read the full paragraph with sequence 1, A, D, B, C. It introduces the forum, names the flaws, expands on how widespread they are, and then shows two different humorous reactions. This flows exactly like a short news explanation. In contrast, starting with jokes before the flaws are even named would make the humour harder to understand and reduce the clarity of the passage.

Why Other Options Are Wrong:
Option CBAD begins directly with one of the jokes, which is confusing before the reader knows what threat is being discussed. Option BCDA also leads with jokes and delays the explanation of Meltdown and Spectre until late in the paragraph, which weakens coherence. Option CADB places the picture before the explanation and the list of affected devices, interrupting the explanatory flow. In all these cases, the reader has to work harder to understand what the gallows humour is about.

Common Pitfalls:
Students sometimes give too much weight to humour or striking images and try to place such sentences early in the order. However, in most expository writing, writers introduce and explain the problem before presenting reactions or examples. Another pitfall is to ignore referents such as that’s most of them, which clearly depends on a previous mention of items that can be counted. Always trace these pronouns back to their logical origins when ordering sentences.

Final Answer:
The correct sequence after sentence 1 is A, D, B, C, so the answer is ADBC.