How many sets of positive integers (a,b,c)(a,b,c)(a,b,c) with a≤b≤ca\le b\le ca≤b≤c satisfy 1a+1b+1c=1?\frac1a+\frac1b+\frac1c=1?a1+b1+c1=1? A111B222C333D444E000F∞\infty∞