Answer:
Option A.
Step-by-step explanation:
Mendelian trait follows the rule of "law of dominance". According to this law,"In a pair of contrasting trait, the one allele may express itself and hides the expression of other allele. The allele that can express itself is dominant allele and the allele that cannot express itself in heterozygous condition is recessive allele".
Detached earlobes allele is dominant over attached earlobe allele. The allele of detached earlobes can express itself in heterozygous condition whereas attached earlobes express itself when present in homozygous condition. Thus, the attached and detached earlobes follows the Mendelian trait.
Hence, the correct answer is option A.