Here is Dave Mulkey’s response to that question:
I have a nice book on my shelf that is about 500 pages about UML. I'm pretty sure that is NOT what is intended.
Judging from specimen paper 2, they just mean Class Diagrams showing inheritance, like the ones that BlueJ draws, or this one:
I think that's what they mean when they say "to represent object designs". It should actually be "class designs".
Here is a pretty standard explanation of UML Class Diagrams:
That covers the relationships mentioned in D.1.6 .
I will teach my students a bit more UML, especially Use Case diagrams and Sequence Diagrams because they are very useful for a programming project, but I wouldn't expect to see those on an exam.
Perhaps a paper-setter / examiner could clarify this for us.