What happens before the dehiscence of anther?

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.

How many microsporangia are located at the corners of a typical bilobed anther of angiosperm?

Which of the following is surrounded by a callose wall?

Describe the internal structure of a microsporangium.

The cells of the sporogenous tissue undergo meiotic division to form microspore tetrads. What would be the ploidy of the cells of the sporogenous tissue?