Explanation:
(B) : The differential equation of all circle \((x-h)^{2}+(y-k)^{2}=a^{2}\)
Since circle lie in the first quadrant and touches both the axis.
Then, center \((\mathrm{h}, \mathrm{k})=(\mathrm{a}, \mathrm{a})\)
Equation of circle,
\((x-a)^{2}+(y-a)^{2}=a^{2}\)
\(\mathrm{x}^{2}+\mathrm{y}^{2}-2 \mathrm{ax}-2 \mathrm{ay}+\mathrm{a}^{2}=0\)
Here, number of arbitrary constant is one
Hence, order is 1