Write a Python program to generate series of marks for 10 students, applying a grace of 5 marks for those with less than 27. Display the new series.
a) Series: PQRSTU, Grace: A-B
b) Series: XYZABC, Grace: LMN-OPQ
c) Series: DEFGHI, Grace: J-K-L
d) Series: MNPQRS, Grace: UVW-XYZ