The government of Country B imposes an income tax of 30% on the net income realized from sources within Country B by foreign persons engaged in business there. Domestic persons (including Country B corporations) are not subject to the income tax. Cosmos Corporation, a U.S. corporation, is engaged in Country B in the business of mining and exporting copper ore through a wholly owned subsidiary organized under the laws of Country B. As a Country B corporation, the subsidiary is exempt from the income tax, but it pays an export tax of $1,000 per ton of the copper ore exported. No portion of this levy is paid in exchange for a specific economic benefit from the government of Country B. No deductions are permitted in calculating this tax, and $1,000 per ton is a rate that is fixed without reference to the market value of the exported copper. Is the export tax creditable?

Would the results in to this question be different if Cosmos Corporation were engaged in the business described through a branch in Country B (rather than through Country B subsidiary) and the branch were subject to the export tax rather than to the income tax?