With a 16t cog the smallest chainring is spec'd to be a 38.. with a 15t its 36t, 17, a 40t.

there is a double reduction gear for 1-7, a single reduction gear for 8-10, 11 is direct , 12-14 is overdrive.

so cog #2 would be 6.5% larger than the minimum specified external drive ratio..
2.35:1 for a single

2.5:1 for a tandem, because of torque from 2 riders it raises the low ratio limit..