Which of the following sentences lacks parallelism?

a. Consumers can download stock research, electronically fi le their tax returns, create a portfolio, or choose from an array of recommended mutual funds.

b. Consumers can download stock research, can electronically fi le their tax returns, create a portfolio, or they can choose from an array of recommended mutual funds.

c. Consumers can download stock research, can electronically fi le their tax returns, can create a portfolio, or can choose from an array of recommended mutual funds.

d. Consumers can download stock research, they can electronically fi le their tax returns, they can create a portfolio, or they can choose from an array of recommended mutual funds.