Square pyramidal geometry is a molecular geometry in which a central atom is surrounded by five ligands arranged in a square base with one additional ligand at the apex, resulting in a pyramid-like shape. Among the given options, the compound that exhibits square pyramidal geometry is Bis(acetylacetonato)oxovanadium(IV) or option D.

Bis(acetylacetonato)oxovanadium(IV) is a coordination compound consisting of a central vanadium atom bonded to two acetylacetonate ligands (acac) and one oxo ligand (O). The acetylacetonate ligands are chelating ligands, meaning they form a ring structure with the central metal atom.

Explanation:
1. Tetracarbonylnickel(0): This compound is a coordination complex where a nickel atom is bonded to four carbonyl ligands. The geometry of this compound is square planar, not square pyramidal.

2. Hexaamminecobalt(II) nitrate: This compound consists of a central cobalt atom bonded to six ammonia ligands (NH3). The geometry of this compound is octahedral, not square pyramidal.

3. Pentacarbonyliron(0): This compound is a coordination complex where an iron atom is bonded to five carbonyl ligands. The geometry of this compound is trigonal bipyramidal, not square pyramidal.

4. Bis(acetylacetonato)oxovanadium(IV): This compound consists of a central vanadium atom bonded to two acetylacetonate ligands and one oxo ligand. The acetylacetonate ligands form a square base around the central vanadium atom, and the oxo ligand is located at the apex, resulting in a square pyramidal geometry. This compound satisfies the criteria for square pyramidal geometry.

In conclusion, among the given options, Bis(acetylacetonato)oxovanadium(IV) is the compound that exhibits square pyramidal geometry.