Pls do it fast its is agrent pls help im not good in maths

step-by-step explanation: 2

true

step-by-step explanation:

intersecting chords are just lines that intersect. so a line is equal to 180 degrees, so when it is intersected by another chord, then it create supplementary angles, and because the lines cross, vertical angels are also formed.

ending amount = beginning amount / (2^n)

where "n" = number of half-lives (or elapsed time / half-life)

ending amount = 50 mg / (2 ^10 / 5.3)

ending amount = 50 mg / (2 ^ 1.8867924528)

ending amount = 50 m / 3.6981210597

ending amount = 13.5203794557 mg

or about 13.5 mg remain

source:  

i believe b is the answer