$$ Jeremy is a calendar year taxpayer. Which of the following statements is true regarding the taxable year the partnership can choose?

a$.$ The partnership must choose an October year$-$end because Fern, Inc, is a principal partner.

b$.$ The partnership must choose the calendar year because it has no principal partners.

c$.$ The partnership must use the least aggregate deferral method to determine its required taxable year:

d$.$ The partnership can request permission from the IRS to use a January $31$ fiscal year under $444.$