(x-a)^2 + (y-b)^2=16 is a circle with its center on (a,b) and radius 4. If this circle is to cut the y axis then y co-ordinate of its center must be less than the radius of the circle.
i.e |a|<4, so question is asking is |a|<4
A. this will not give any information about a alone. So this can no be sufficient.
INSUFFICIENT
B. a=|b|+5
|b| will be always non-negative so |b|+5>=5
So a is always greater than 5, i.e. a>5 so this option sufficient information to tell that the
circle will never cut the y axis.
SUFFICIENT
Answer B
Sometimes there is very fine line between right and wrong: perspective.
