I need help with this Non-Verbal- 11+ question???

[Rednosebunny]

Hi there anyone,
has anyone got the Nfer Nelson Non- Verbal- Reasoning (multiple choice) practise papers handy?
Question: Test 11A, Section 5, question 11.
The answer is d but we fail to understand why??
And certainly cannot explain to my son a good possible answer.

Grateful for any feedback

Can you just type it out?- more people might be able to help then.

Sorry, can't as it's non-verbal- reasoning.
It's the set of questions where one needs to find the most alike to the two example shapes

Scan it in? Take a picture with your mobile?

Two logics:

1. Must be a horizontal base
2. The shading lines are not parallel to the diagonal line.

C and D can be shortlisted. But D satisfies the above logics.

LadyMuck,thanks so much for answering!!
your answers definitely make much more sense than mine.......