You need to retrieve a list of photos from an API. Which code snippet defines an HTML GET request in Retrofit?
a. @GET("photo/{id}"} fun listPhotos(@Path("id") id:Long?) : Call
b. @LIST("photo") fun listPhotos() : Call<List>
c. @GET("photo") fun listPhotos() : Call
d. @GET("photo") fun listPhotos() : Call<List>