What is the ploidy of a male gamete?

Examine the figure given below and select the right option identifying all the four parts $a, b, c$ and $d$.

Which of the following parts is not a component of the stamen?

Given below are two statements.
Statement $I$: Generally,anthers in angiosperms are dithecous,having two pollen sacs in each lobe.
Statement $II$: Each sporangium produces pollens from sporogenous tissues by the process of sporogenesis.
In light of the above statements,select the correct answer from the options given below.

Which one of the following statements is correct?

In angiosperms,the male gametophyte is shed at which stage?