The mole concept establishes that one mole of any substance contains Avogadro's number ((6.022 \times 10^{23})) of particles and has a mass equal to the molar mass in grams. Carbon dioxide ((\text{CO}_2)) has a molar mass of (12 + 2 \times 16 = 44 \text{ g mol}^{-1}). Therefore, 44 g of (\text{CO}_2) corresponds to (44/44 = 1.0) mol. Option 0.5 mol is incorrect because it would correspond to only 22 g of (\text{CO}_2), not 44 g. Option 2.0 mol is wrong because that would require 88 g of (\text{CO}_2). Option 4.0 mol is also incorrect as it would require 176 g. This calculation directly applies the NCERT definition of molar mass: the mass in grams of one mole of a substance numerically equals its molecular mass in atomic mass units. Plausibility check: 44 g divided by 44 g/mol gives exactly 1.0 mol, confirming the answer is dimensionally consistent and numerically correct.