Answer:
The rhyme scheme for this case will be as follows:
"But thy eternal summer shall not fade, - A
Nor lose possession of that fair thou ow'st, - B
Nor shall death brag thou wander'st in his shade, - A
When in eternal lines to time thou grow'st, - B
So long as men can breathe or eyes can see, - C
So long lives this, and this gives life to thee." - C
Step-by-step explanation:
The rhyme pattern used by the author was an alternate rhyme pattern on the first four verses and at the end he uses a couplet in the last two verses (CC).