Which factor is least likely to directly affect claim cost?

The age of an applicant's dependants is least likely to directly affect claim cost compared to the other factors listed. In insurance, claim costs are typically influenced more directly by the applicant's own characteristics, such as their age, sex, and occupation.

The age of the policyholder can impact the likelihood of claims due to varying health risks associated with different life stages. Similarly, sex may play a role in statistical risk assessments, as different genders can have differing probabilities of certain health outcomes or accident rates. Occupation is also a significant factor, as certain jobs may be associated with higher risks of injury or liability, leading to potentially higher claim costs.

While the ages of dependants might indirectly be considered when evaluating family coverage or potential impacts on life insurance, they are not a primary determinant of the costs associated with claims made under the policy. Therefore, among the options, the age of the applicants' dependants has the least direct influence on claim costs.