A buy$-$side analyst values information from a sell$-$side analyst because $\_\_\_\_\_\_\_.$

a$.$ sell$-$side analysts have a very broad knowledge base that covers wider moats than the buy$-$side analysts

b$.$ sell$-$side analysts have an incentive to provide negative information about the companies they cover

c$.$ sell$-$side analysts often pay for and have access to data the buy$-$side analyst does not have

d$.$ sell$-$side analysts do not publish their reports, so buy$-$side analysts need to meet with them to gather information on the companies they cover