An inspector from the insurance department uncovers evidence of the following activities by an insurance company. Which of them is not an unfair claims practice?

a$.$ ignoring calls from claimants in the belief that a certain proportion of them will get tired of calling and drop their claim

b$.$ telling an insured that his policy had expired when, in fact, it is still in force

c$.$ requiring that the insured submit proof of loss

d$.$ directing an insured to a repair contractor who uses shoddy materials because they are cheaper