If the positive numbers x,y,z are in harmonic progression, then $$\mathrm{log}(x+z)+\mathrm{log}(x-2y+z)$$ equals

$$a)4\mathrm{log}(x-z)\phantom{\rule{0ex}{0ex}}b)3\mathrm{log}(x-z)\phantom{\rule{0ex}{0ex}}c)2\mathrm{log}(x-z)\phantom{\rule{0ex}{0ex}}d)\mathrm{log}(x-z)$$

How do i approach this problem? IF x,y,z are in HP, $$\Rightarrow y=2xy/x+z$$

$$a)4\mathrm{log}(x-z)\phantom{\rule{0ex}{0ex}}b)3\mathrm{log}(x-z)\phantom{\rule{0ex}{0ex}}c)2\mathrm{log}(x-z)\phantom{\rule{0ex}{0ex}}d)\mathrm{log}(x-z)$$

How do i approach this problem? IF x,y,z are in HP, $$\Rightarrow y=2xy/x+z$$