Which TWO lines in this excerpt suggest the physical union of the lovers?

The Flea

by John Donne (excerpt)

Mark but this flea, and mark in this,

[ (a.) How little that which thou deniest me is; ]

Me it sucked first, and now sucks thee,

[ (b.) And in this flea our two bloods mingled be; ]

Thou know'st that this cannot be said

[ (c.) A sin, or shame, or loss of maidenhead; ]

Yet this enjoys before it woo,

[ (d.) And pampered swells with one blood made of two;

And this, alas, is more than we would do.]

The correct answers are

[ (b.) And in this flea our two bloods mingled be; ]

Thou know'st that this cannot be said

and

[ (d.) And pampered swells with one blood made of two;

And this, alas, is more than we would do.]

In this poem, the flea clearly symbolizes their love.

In the answer (b.), their bloods are mixed in this flea and this could metaphorically signify mixing their bodily fluids while engaging in intercourse.

In the answer (d.), it is clear that the speaker is denied intercourse with this woman and extends his argument from the sentence (b.) that their bloods mixed in the flee signify their physical union and that, despite what the society might suggest about her loss of virginity, there is nothing shameful about this act.