"This is also why several XML tools are available from various manufacturers." This is why several XML tools * can be obtain from* from various manufacturers. available =

You have choices of manufacturers to buy from. Example Smartphones in USA-few brands of phones if you wanted a smartphone to choose from: LG Samsung, iphones Motorola zte windows phones

Your answer is correct Wing - "several XML tools are available from various manufacturers" means the same as "several XML tools are manufactured by different manufacturers". But don't forget you need to look at the words "This is also why..." at the beginning of the sentence. Hope this helps. Chris

'available from' means 'can be purchased from' 'can be got from' or 'can be supplied by'. So the entire sentence means something like: 'this is the reason why you can get one of several different XML tools, from several different suppliers.