Suppose p r o d u c t s is a dictionary that maps the names of products for sale in a store ot their respective prices. Which one of hte folowing would test whether $"$ phone'$)$ is akey ni products?phone inproductsproducts.contains $(\text{'}$ phone'$)\text{'}$phone$\text{'}==$ products. keys $()$products$.$ index $(\text{'}$ phone'$)$