Answer
In the provided statements, consider p as some journalists learn about the invasion, q as the newspapers will print the news, r as the invasion was a secret,\[\tilde{\ }p\]as no journalists learned about the invasion, and \[\tilde{\ }r\]as the invasion will not be a secret. Therefore, express the premises and conclusion symbolically.
\[\begin{align}
& \,p\to q \\
& \frac{\begin{align}
& q\to \tilde{\ }r \\
& \sim p \\
\end{align}}{\therefore \,r} \\
\end{align}\]
Here, sign \[\to \] denotes conditional means (if….then….), sign\[\sim \]denotes negation means it makes the sentence negative. The argument is basically transitive argument, i.e., it should be\[\sim r\], but the obtained conclusion is \[r\].
Therefore, it is a misuse of transitive argument.
Hence, the argument is invalid