Option D is the answer because Digital Certificate is an entity that generates electronic and distributes them upon proving their identity sufficiently. In early days there was issues with people using the certificates that were not even issued by the organizations. Today it's a cryptographic technique which uses digital signatures and gives users a digital certificate that can be authenticated anytime online by any organization and is unique for every user having it.
Option A cannot be the answer because it has nothing to do with the identity of person but rather it is for specific fields.
Option B is not answer because it has no key and score matter to do with it.
Option C Web transactions has nothing to do with the certificates.
The answer to this question is firewall
This depends on what program you're using. Some programs can only read certain files exclusive to that program, such as .psd files can usually only be read in Photoshop or other adobe programs. Many fields of work (Journalism, the Arts, Design, etc.) ask for .psd files to be converted to either .png, .jpg, or .tiff so that it can be seen on many other platforms.
For images especially, files are more compatible either on a program or printed. for example, .png files are good for storing color data from computer to computer, but if you print a .png file, the quality is poor. hence it's recommended to save files you want to print for designs as .jpeg, because .jpeg can more easily be printed and will then be presented at a high quality.
Sometimes color quality changes depending on CMYK as well but that's a whole other ball of wax.
When energy flows in the Electric Circuit then Light bulb blows and emits light energy and thermal energy. By that sign, we can get an idea that energy is flowing.
Hope this helps!
