__ PbO+ ___ HNO₃ → ___ _Pb(NO₃)₂ + ___ H₂O

e imma say squidward tentacles

a they donate money to humanitarian causes

c   they volunteer to alleviate suffering

d   they blame all muslims for not being able to keep their fellow muslims in line.

so, based on the research i've done. the u.s. government were always on a wild goose chase just to take down castro. he then retired his trone to his brother raul in 2008 due to some health issues. so it's obvious your answer would be:

castro had no allies from which he could receive aid.

hope this and have a fantastic day!

                                                    -wolfiewolffromsketch