4. (1) Scientists say grilling meat creates cancer-causing substances that affect the meat in two ways. (2) First, when fat drips onto the source of heat, the substances are formed and then carried up to the food by smoke. (3) They are also formed when flames touch the meat. (4) There are, however, a few ways that experts say will minimize the risk of grilling meat: (a) Use low-fat meats and nonfat sauces. (5) (b) Partially cook meat before grilling. (6) (c) Cover the grill with foil; punch holes in the foil to let fat drip down. (7) (d) Avoid fire flare-ups, which cause harmful smoke. (8) (e) Scrape off blackened material on the surface of meat before eating it. (9) (f) Don’t cook out every day.

The tone of this passage is

a. optimistic.

b. distressed.

c. objective.