Mark the letter A, B, C, or D to indicate the sentence that best combines each pair of sentences in the following questions

A. Electronic dictionaries which can be very easily downloaded into your personal electronic device are now common in English classes.

B. Electronic dictionaries, which can be very easily downloaded into your personal electronic device, are now common in English classes.

C. Electronic dictionaries, that can be very easily downloaded into your personal electronic device, are now common in English classes.

D. Electronic dictionaries can be very easily downloaded into your personal electronic device are now common in English classes.

A. Electronic devices that their radiation is very harmful are bad for your eyes.

B. Electronic devices which their radiation is very harmful are bad for your eyes.

C. Electronic devices, whose radiation is very harmful, are bad for your eyes.

D. Electronic devices whose radiation is very harmful are bad for your eyes.