a) You will create a DTD from scratch. Write the correct DTD declaration for each of the following descriptions. (Your answers should NOT be XML elements!) Declare an element e which has string content: Declare an element d which cannot have any content: Declare an element c which contains precisely one e followed by possibly one d: Declare an element b which has mixed content, namely strings mixed with any number of e elements: Declare an element a whose content will be a choice between a sequence of (one or more c, then one d, then 0 or more e, then one b) and a sequence of (one b, then one d, then one c): b) Write a minimal XML document that would validate against the DTD from question a)