For each pair of positive integers a and b, we can find unique integers q and r satisfying the relation
a=bq+r,0≤r<b
If r=0 then q will be HCF of a and b
The basis of the Euclidean division algorithm is Euclid’s division lemma.
To calculate the Highest Common Factor (HCF) of two positive integers a and b we use Euclid’s division algorithm.
HCF is the largest number which exactly divides two or more positive integers.
By exactly we mean that on dividing both the integers a and b by HCF, the remainder is zero.
So correct answer is option A