The formula $P_k = y_0 + k \triangledown y_0+ \frac{k(k+1)}{2} \triangledown ^2 y_0 + \dots + \frac{k \dots (k+n-1)}{n!} \triangledown ^n y_0$ is
Answer is A
Newton-Gregory backward difference interpolation polynomial formula
http://nptel.ac.in/courses/122104019/numerical-analysis/Rathish-kumar/rathish-oct31/fratnode9.html
A) Newton's backward formula