Compared to Standard Linkage Analysis Methods,what Is an Advantage of the Affected

Compared to standard linkage analysis methods,what is an advantage of the affected sib pair method for gene hunting in complex traits?

A) Smaller samples are required
B) You can use two affected individuals from one family
C) No model specification is required for the mode of inheritance
D) Siblings who are discordant for the trait provide information for the analysis
E) Fewer markers need to be genotyped