Answer:
B. Skull.
Step-by-step explanation:
The painting The French Ambassadors by Hans Holbein the Younger includes a variety of items, including:
Two globes (one terrestrial and one celestial)
A shepherd's dial
A quadrant
A torquetum
A polyhedral sundial
A lute
A hymn book
A book of arithmetic
An Oriental carpet
A floor mosaic based on a design from Westminster Abbey
However, there is no skull in the painting.
The other options are all included in the painting:
Musical instrument: lute
Sword: Jean de Dinteville is wearing a sword at his side.
Therefore, the answer is OB. Skull.