To answer this question, let's go through each option to understand why it is correct or incorrect:

Option A) Change the permissions on all the .jpg file so that it is readable. - This option is correct. The chmod command is used to change the permissions of files and directories in Unix-like operating systems. In this command, og+r sets the read permission (r) for the owner (o) and the group (g) of each file. By using *.jpg, it selects all files with the .jpg extension, and changes their permissions to be readable.

Option B) It is not a valid command because the file name contains a . - This option is incorrect. The use of `` as a wildcard character is a valid syntax in Unix-like operating systems. It allows the command to be applied to multiple files or directories that match the specified pattern.

Option C) Change the permissions on all image files. - This option is incorrect. The command specifically targets files with the .jpg extension, not all image files. Only the permissions of the .jpg files will be changed, not other image files.

Option D) Change permissions on the directory so that image files can be saved in it. - This option is incorrect. The chmod command does not change the permissions of the directory itself, but rather the permissions of the files within that directory.

The correct answer is A) Change the permissions on all the .jpg file so that it is readable. This option is correct because the chmod og+r *.jpg command will change the permissions of all .jpg files, making them readable.

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• Wrong explanation

To determine how many times "Hello World!" will be printed, let's analyze the given code.

In the code, the fork() function is called three times consecutively. Each time the fork() function is called, it creates a new process by duplicating the existing process. So, the first fork() call creates one child process, the second fork() call creates two child processes (one from the original process and one from the child process of the first fork() call), and the third fork() call creates four child processes (one from the original process, two from the child processes of the second fork() call, and one from the child process of the first fork() call).

Therefore, a total of 1 + 2 + 4 = 7 child processes are created, in addition to the original process. Since each process executes the printf("Hello World!"); statement, it will be printed 8 times in total.

So, the correct answer is D) 8.

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• Wrong explanation