d. they permit direct estimation of risk of disease in those exposed to the suspected factor.
Explanation:
A major advantage of cohort studies over case-control studies with respect to the role of a suspected factor in the etiology of a disease is that they permit direct estimation of risk of disease in those exposed to the suspected factor.
This is on account of intense social solidarity requests that a few people be rejected. By declaring they were altogether related-this is, by barring nobody Arembepeiros were really debilitating connections' potential quality in making and keeping up gather solidarity.