External search effort associated with purchase is greatest when consumers have high product category knowledge consumers do not care about the purchase the purchase situation is low-risk product category knowledge is low subjective knowledge is high

Product category knowledge is low.

Explanation:

External search effort associated with purchase is greatest when product category knowledge is low. Consumers need to have a product category knowledge when making a purchase. If not, the external search effort would be greater, and extrinsic cues would be necessary to make product choices. When consumers have high knowledge, the external search effort is lower.