Your answer would be A for your homework
Answer:

Explanation:
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In this case, for the given reactants side, we infer this is a double replacement reaction because all the cations and anions are switched around as a result of the chemical change, we infer that the products side include aluminum with nitrate and magnesium with sulfate as shown below:

However, we need to balance since unequal number of atoms are present at both sides, thus, we do that as shown below:

Thus, we make 6 Al atoms, 3 S atoms, 3 Mg atoms and 30 O atoms on each side in agreement with the law of conservation of mass.
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If 0.25mg of atropine is in 1mL
so
0.50mg of atropine is in x