URGENT PLZ HELP

The pH of a liquid is a measure of how acidic or basic it is. The concentration of hydrogen ions in a liquid is labeled (H+). Use the formula pH = -log[H] to find the pH level, to the nearest tenth, of a liquid with [H] about 8.1 x 10-7,

a = 6.1
b = 7.9
с = -7.9
d = 7.0