You have one of pure elemental metals (made of identical atoms; e. g. Ni, Cr, Pt, Al, Cu, Ta, Na, etc.). It has a Cubic (a=b=c, α=β=γ=90o ) crystal system. From the accompanying XRD data (taken with Cu K-α radiation λ = 1.5418Å),

a. Determine the crystal structure (i. e., choose from Simple Cubic, Base-centered Cubic, Body-centered Cubic, Face-centered Cubic, etc.) of the material.
b. Index each peak (i. e., assign hkl on each peak).
c. Calculate the lattice parameter, a. 2θ: 43.16, 50.30, 73.99, 89.85, 95.03, 116.92, 136.59