If some words are coded from artificial language, like

"ningl abubk" means emergency time

"abubk lontg" means operation time

"ningl pntuo" means emergency ward

Which code could means "operation done" ?

hustil lontg

We have,

"ningl abubk" means emergency time

"abubk lontg" means operation time

"ningl pntuo" means emergency ward

If we see clearly,

Statement "abubk lontg" means operation time contains operation word so, code for operation must be abubk or  lontg , but they can not come altogether in a single statement because we have to find the code for operation done.

Here no information about Done is given and also Done will be coded as the word which is not present in the paragraph. So if we check option C there is both abubk and lontg. which is not possible.

So, hustil lontg is the right code.