"一択" meaning in Japanese

{
  "forms": [
    {
      "form": "一択",
      "ruby": [
        [
          "一択",
          "いったく"
        ]
      ],
      "tags": [
        "canonical"
      ]
    },
    {
      "form": "ittaku",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "いったく"
      },
      "expansion": "一択(いったく) • (ittaku)",
      "name": "ja-noun"
    }
  ],
  "lang": "Japanese",
  "lang_code": "ja",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Japanese entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Japanese links with redundant wikilinks",
          "parents": [
            "Links with redundant wikilinks",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Japanese terms with redundant sortkeys",
          "parents": [
            "Terms with redundant sortkeys",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "the only choice, the one possible option"
      ],
      "id": "en-一択-ja-noun-6M6ltDTH",
      "raw_glosses": [
        "(slang) the only choice, the one possible option"
      ],
      "tags": [
        "slang"
      ]
    }
  ],
  "word": "一択"
}

{
  "forms": [
    {
      "form": "一択",
      "ruby": [
        [
          "一択",
          "いったく"
        ]
      ],
      "tags": [
        "canonical"
      ]
    },
    {
      "form": "ittaku",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "いったく"
      },
      "expansion": "一択(いったく) • (ittaku)",
      "name": "ja-noun"
    }
  ],
  "lang": "Japanese",
  "lang_code": "ja",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Japanese entries with incorrect language header",
        "Japanese lemmas",
        "Japanese links with redundant wikilinks",
        "Japanese nouns",
        "Japanese slang",
        "Japanese terms spelled with first grade kanji",
        "Japanese terms spelled with secondary school kanji",
        "Japanese terms with redundant sortkeys",
        "Japanese terms written with two Han script characters"
      ],
      "glosses": [
        "the only choice, the one possible option"
      ],
      "raw_glosses": [
        "(slang) the only choice, the one possible option"
      ],
      "tags": [
        "slang"
      ]
    }
  ],
  "word": "一択"
}

{
  "called_from": "parser/1336",
  "msg": "no corresponding start tag found for </span>",
  "path": [
    "一択"
  ],
  "section": "Japanese",
  "subsection": "noun",
  "title": "一択",
  "trace": ""
}