Choose the most appropriate option to change the narration (direct / indirect) of the given sentence.

Shubham said to me, " I had to blend the pulp and prepare the juice."

a) Shubham told me that he has to blend the pulp and prepare the juice.
b) Shubham told me that he had to blend the pulp and prepare the juice.
c) Shubham told me that he had had to blend the pulp and prepare the juice.
d) Shubham told me that he will have to blend the pulp and prepare the juice.