For I assure you (what credit my assurance may have with
you, I cannot tell, but what credit it shall deserve to have,
the sequel shall declare) I will never in that matter concludes
any thing that shall be prejudicial to the realm. For the
weal, good and safety whereof, I will never shun to spend
my life, and whomsoever it shall be my chance to light
upon, I trust he shall be such, as shall be as careful for the
realm as you; I will not say as myself, because I cannot so
certainly determine of any other, but by my desire he shall
be such as shall be as careful for the preservation of the
realm and you, as myself

If your question is about Queen Elizabeth's purpose in this excerpt, the correct answer is C. to persuade her audience that she will not make any personal choices that harm England.

Explanation:

The Parliament bid the queen to marry and produce an heir not just because it was a social convention at the time, but because they believed it was in the best interest of England and all English people. In this speech, the queen turns this argument on its head, saying that she indeed intends to act in England's best interest, and that her marriage or lack thereof won't affect the state politics in any way. Her personal choice, therefore, has nothing to do with her high office.

If you are looking for the common purpose of this and the excerpt from Queen Elizabeth’s Address to the Troops at Tilbury, then the answer is B. I am come amongst you, as you see, at this time, not for my recreation and disport, but being resolved in the midst and heat of the battle, to live or die among you all. This excerpt shows that she is willing to sacrifice her own life if need be. She explicitly says that she hasn't come for "recreation and disport" - therefore, for entertainment or putting on a show.