An elastic band is hung on a hook and a mass is hung on the lower end of the band. When the mass is pulled downward and then released, it vibrates vertically. The equation of motion is s = 7 cos(t) + 6 sin(t), where s is measured in centimeters and t is measured in seconds. (Take the positive direction to be downward.)

When does the mass pass through the equilibrium position (the position when the system is at rest) for the first time? (Round your answer to two decimal places.)

(a) 0.50 seconds
(b) 0.90 seconds
(c) 1.30 seconds
(d) 1.70 seconds