The DNA content of a diploid cell in the G1 phase of the cell cycle is measured. If the DNA content is x, then the DNA content at metaphase of meiosis II would be:

2x

Explanation:

The G1 phase is a part of the interphase stage of the cell cycle, where the cell undergoes resting and preparation prior to division. Before division can occur, the cell needs to replicate its genetic material (DNA). The cell does this at the S-PHASE, after the First Gap or G1 phase.

The cell duplicates its DNA in order to ensure that each daughter cell receives equal and correct number of chromosomes (DNA). Hence, if the measured DNA at G1 phase was (x), it replicates/doubles I. e x+x or x * 2 = 2x.

Therefore, at the Metaphase phase (division), the DNA content will be 2x before they separate in the anaphase stage.