Which of the following compounds reacts with ethylmagnesium bromide and also decolourizes bromine water solution:

The major product of the following reaction is :

The major product obtained in the following reaction is :

The coordination number of Th in K₄[Th(C₂O₄)₄(OH₂)₂] is :
(C₂O$${_4^{2 - }}$$ = Oxalato)