Question: what is the number of basic units in the international system of units
[{'answer': 'seven', 'provenance': [{'wikipedia_id': '26872', 'title': 'SI base unit', 'start_paragraph_id': 1, 'start_character': 22, 'end_paragraph_id': 1, 'end_character': 27, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '26872', 'title': 'SI base unit', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 411, 'bleu_score': 0.7520459990153591, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9782416657609897166}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '44142', 'title': 'Metric system', 'section': 'Section::::Abstract.', 'start_paragraph_id': 7, 'end_paragraph_id': 7, 'meta': {'evidence_span': ['The modern metric system consists of four electromechanical base units representing seven fundamental dimensions of measure: length, mass, time, electromagnetism, thermodynamic temperature, luminous intensity, and quantity of substance.', 'The modern metric system consists of four electromechanical base units representing seven fundamental dimensions of measure: length, mass, time, electromagnetism, thermodynamic temperature, luminous intensity, and quantity of substance.', 'The modern metric system consists of four electromechanical base units representing seven fundamental dimensions of measure: length, mass, time, electromagnetism, thermodynamic temperature, luminous intensity, and quantity of substance.']}}]}, {'provenance': [{'wikipedia_id': '13314856', 'title': 'Unified Code for Units of Measure', 'section': 'Section::::Base units.\n', 'start_paragraph_id': 5, 'end_paragraph_id': 5, 'meta': {'evidence_span': ['Also an OSGi based implementation at Eclipse Foundation. Units are represented in UCUM with reference to a set of seven base units.', 'Units are represented in UCUM with reference to a set of seven base units.', 'Units are represented in UCUM with reference to a set of seven base units']}}]}, {'provenance': [{'wikipedia_id': '26872', 'title': 'SI base unit', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['The SI base units are seven units of measure defined by the International System of Units as the basic set from which all other SI units can be derived', 'The SI base units are seven units of measure defined by the International System of Units as the basic set from which all other SI units can be derived.', 'The SI base units are seven units of measure defined by the International System of Units as the basic set from which all other SI units can be derived.']}}]}, {'provenance': [{'wikipedia_id': '26876', 'title': 'SI derived unit', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['SI derived units are units of measurement derived from the seven base units specified by the International System of Units (SI).', 'SI derived units are units of measurement derived from the seven base units specified by the International System of Units (SI).', 'SI derived units are units of measurement derived from the seven base units specified by the International System of Units (SI).']}}]}]