Correct option is D
Boiling points of ethers having molecular mass equal to or less than n-butane (i.e., 58 g mol-1) are higher than those of the corresponding n-alkanes. however, the boiling points of ethers having molecular mass equal to or higher than n-pentane (i.e., 72 g mol-1) are lower than the corresponding n-alkanes . thus, b.p. of n-butane is lower than that of ethoxyethane. further, the b.ps of alcohols are much higher than those of alkanes, and ethers of comparable molecular masses due to intermolecular H-bonding. however, b.ps of aldehydes are lower than those of corresponding alcohols due to absence of H-bonding but are still higher than those of alkanes and ethers of comparable molecular mass. Thus, the overall increasing order of b.pt is
n-butane, ethoxyethane, pentanal, pentan-1-ol.
