Intestacy with no spouse, issue or parent: whole-blood sibling's issue before half-blood sibling

Gethin left no spouse or civil partner, no issue and no parent, so s.46(1)(v) Administration of Estates Act 1925 applies. The estate is held first 'on the statutory trusts for the brothers and sisters of the whole blood of the intestate', and only if no one takes an absolutely vested interest under those trusts does it pass to siblings of the half blood, then grandparents. Under s.47(1)(i) and (3), the statutory trusts for siblings include the issue of a sibling who predeceased the intestate, who take by representation the share their parent would have taken. Rhodri was Gethin's brother of the whole blood; his adult children, Siân and Owain, take his share and attain vested interests. Because someone takes under the whole-blood class, the half-blood class (Mererid) and the grandparents (Gwen) are excluded. Siân and Owain therefore share the whole estate equally.

Why A is wrong: Half-blood siblings take only if no one takes a vested interest under the statutory trusts for whole-blood siblings, which include Rhodri's issue.

Why B is wrong: Grandparents come third in s.46(1)(v), after both classes of siblings and their issue.

Why C is wrong: There is no sharing between classes; the whole-blood class takes everything and excludes the half blood.

Why D is wrong: Mererid is in a later class, and Siân and Owain take only their father's share between them, not shares per head alongside other classes.