if 1 g is equal to 100 cg
then 0.55 g are equal to X cg
X = (0.55 × 100 ) / 1 = 55 cg
The density of the object is 55 cg/L.
The reaction for burning of charcoal or complete combustion is as follows:

From the above balanced reaction, 1 mole of carbon releases 1 mole of
gas.
Converting mass of charcoal into moles as follows:

Molar mass of pure carbon is 12 g/mol thus,

The same moles of
is released. Converting these moles into mass as follows:
m=n×M
Molar mass of
is 44 g/mol thus,

Converting mass into kg,

Thus, total mass of gas released is 5.5 kg.
Reactions happen instantly even if some are slower than others they all happen instantly so the answer would be A.
Could you show the characteristics?